In determining whether the covenant is reasonable, it is necessary to consider whether enforcement will be injurious to the public or cause undue hardship to the covenantor, and whether the restraint imposed is greater than necessary to protect the covenantee. (See House of Vision, Inc. v. Hiyane (1967), 37 Ill.2d 32, 225 N.E.2d 21.) The court must consider, in the circumstances of each case, the legitimate interests of the covenantee which might be protected by the covenant and the protection granted by the covenant in terms of time, space and the types of activity proscribed. ( Smithereen Co. v. Renfroe (1945), 325 Ill. App. 229, 59 N.E.2d 545.) Whether the covenant will be deemed enforceable depends upon the totality of these circumstances. I.

"An agreement by which an employee, as part of his contract of employment undertakes not to enter into a competing business on leaving his employment usually is valid if its provisions are reasonable, necessary for the employer's protection, and not injurious to the public interests. (William N. Frye, Inc. v. Weber, 1951, 96 N.E.2d 579, 342 Ill. App. 303; Smithereen Co. v. Renfroe, 59 N.E.2d 545, 325 Ill. App. 229; Jules Chain Store Corporation v. Stone, 43 N.E.2d 849, 316 Ill. App. 45; Hoops Tea Co. v. Dorsey, 99 Ill. App. 181). This rule has been applied to agreements by salesmen.

In the other case cited by defendant, Valdez v. Viking Athletic Ass'n, 349 Ill. App. 376, 110 N.E.2d 680, a letter from the prospective employer to the prospective employee, which did not require the employee to report for duty at any specific time, was held too indefinite, uncertain and lacking in mutuality, and therefore unenforceable. Both the plaintiff and defendant cite the case of Smithereen Co. v. Renfroe, 325 Ill. App. 229, 59 N.E.2d 545. In that case it was held the contract was made in consideration of the employment of the defendant by the plaintiff.

Justice Johnson, Justices McMorrow and Jiganti concurring, affirmed the trial court's holding, inter alia, that the non-compete covenant was supported by adequate consideration. Justice Johnson, for the First District, based the decision on the fact that the defendant continued to work for almost four years after signing the contract. The Millard court relied on the cases of Corroon Black, Inc. v. Magner, 145 Ill. App.3d 151, 494 N.E.2d 785, 98 Ill.Dec. 663 (1st Dist. 1986), McRand, Inc. v. van Beelen, 138 Ill. App.3d 1045, 93 Ill.Dec. 471, 486 N.E.2d 1306 (1985), Office Electronics, Inc. v. Grafic Forms, Inc., 56 Ill. App.3d 395, 372 N.E.2d 125, 14 Ill.Dec. 320 (2nd Dist. 1978), and Smithereen Co. v. Renfroe, 325 Ill. App. 229, 59 N.E.2d 545 (1st Dist. 1945) in support of its holding that continued employment for a substantial period is sufficient consideration to support an employment agreement. Millard, 566 N.E.2d at 384, 152 Ill.Dec. at 697.

l.App.2d 364 [ 261 P.2d 351]; Mason v. Rolando Lumber Co., 111 Cal.App.2d 79 [ 243 P.2d 814]; Hunter v. Sparling, 87 Cal.App.2d 711, 725 [ 197 P.2d 807]; Weintraub v. Soronow, 115 Cal.App. 145, 151 [ 1 P.2d 28]; 1 Witkin, Summary of California Law, § 221, pp. 249-259; Eastern Woodworks v. Vance (1955), 206 Md. 419 [ 112 A.2d 231, 235]; Harris v. Kirshner (1949), 194 Md. 139 [ 70 A.2d 47, 49]; Perreault v. Hall (1946), 94 N.H. 191 [ 49 A.2d 812, 813]; Roessler v. Burwell (1934), 119 Conn. 289 [ 176 A. 126]; Palumbo v. George A. Fuller Co. (1923), 99 Conn. 353 [ 122 A. 63, 67]; Platts v. Arney (1955), 46 Wn.2d 122 [ 278 P.2d 657]; Harlow Pub. Co. v. Patrick (1937), 181 Okla. 83 [ 72 P.2d 511]; Woodward v. Vegetable Packing House (1958), 4 Wis.2d 36 [ 90 N.W.2d 586]; Nelson v. Farmers Mutual Auto. Ins.Co. (1958), 4 Wis.2d 36 [ 90 N.W.2d 123, 131]; Johnson v. Quaal (1957), 250 Minn. 154 [ 83 N.W.2d 796]; Waites v. Miller (1928), 244 Mich. 267 [ 221 N.W. 171, 173]; SmithereenCo. v. Renfroe (1945), 325 Ill. App. 229 [ 59 N.E.2d 545]; Jackson v. First Nat. Bank Trust Co. of La Porte (1944), 115 Ind. App. 313 [ 57 N.E.2d 946]; Clark v. J. C. Auditore (1927), 244 N.Y. 382 [ 155 N.E. 679] (did parties intend to be bound by this agreement); Beni v. Frasca (1940), 259 App. Div. 844 [19 N.Y.S.2d 223, 228]; Hooper v. Bell (1948, Tex.Civ.App.), 210 S.W.2d 870, 875; Casper Nat. Bank v. Curry (1937), 51 Wyo. 284 [ 65 P.2d 1116, 110 A.L.R. 360]; GeneralPaint Corporation v. Kramer (10th Cir., 1932), 57 F.2d 698.)

We disagree because we find that the cases cited by the plaintiff in which covenants not to compete have been enforced are not analogous to the situation in the instant case. In Smithereen Co. v. Renfroe (1945), 325 Ill. App. 229, 59 N.E.2d 545, relied upon by the plaintiff, the court found that the covenant not to compete should be enforced. That case, however, differs substantially from the instant case because the court decision was based, at least in part, on the fact that the former employee had acquired certain confidential information that he had attempted to use for his own benefit.

This difference between Illinois and Delaware law was not a problem for the district judge because he concluded that Curtis had demonstrated a protectable interest and had thus satisfied the more demanding standard. But he also concluded that the covenant not to compete was invalid under Illinois law because not supported by consideration. He recognized that several decisions by Illinois's intermediate appellate court have found covenants not to compete to be adequately supported by consideration in circumstances indistinguishable from those in this case, Millard Maintenance Service Co. v. Bernero, 207 Ill. App.3d 736, 152 Ill.Dec. 692, 697-98, 566 N.E.2d 379, 384-85 (1990); Corron Black, Inc. v. Magner, 145 Ill.App.3d 151, 98 Ill.Dec. 663, 494 N.E.2d 785, 791 (1986); McRand, Inc. v. Van Beelen, 138 Ill.App.3d 1045, 93 Ill.Dec. 471, 478-79, 486 N.E.2d 1306, 1313-14 (1985); Smithereen Co. v. Renfroe, 325 Ill. App. 229, 59 N.E.2d 545, 551 (1945), and he did not attempt to distinguish those cases. But he was sure that the state's highest court, should it ever take such a case, would throw out the line of intermediate-court decisions as contrary to the fundamental principles of contract law, which with immaterial exceptions refuses to enforce contracts for which there is no consideration.

Plaintiff also cites two cases in which Illinois courts used arguably non-confidential customer information to justify enforcing a restrictive covenant, but these cases predate Illinois's adoption of a legitimate business interest requirement. Compare Wessel Co. v. Busa, 28 Ill. App. 3d 686, 690, 329 N.E.2d 414, 417 (1st Dist. 1975) (decided April 23); Smithereen Co. v. Renfroe, 325 Ill. App. 229, 243, 59 N.E.2d 545, 550 (1st Dist. 1945) with Nationwide Advertising Service, Inc. v. Kolar, 28 Ill. App. 3d 671, 673, 329 N.E.2d 300, 301-02 (1st Dist. 1975) (decided May 1, and cited as the first appearance of the legitimate business interest requirement in Illinois law by Lifetec, 377 Ill. App. 3d at 276, 880 N.E.2d at 201 (Steigmann, J., concurring)) This opinion addresses pricing information separately from customer requirements and other information about customers.

It is elementary contract law that an agreement too indefinite and vague for enforcement may be made definite by performance. Smithereen Co. v. Renfroe, 325 Ill. App. 229, 59 N.E.2d 545 (1945); Arthur Rubloff Co. v. Leaf, 347 Ill. App.? 191, 106 N.E.2d 735, 737 (1952), and that performance of a contract takes it out of the statute of frauds. Pearce v. Pearce, 184 Ill. 289, 56 N.E. 311 (1859).

We believe this covenant satisfies both tests defined above and must be considered an effective waiver. Under Illinois law, a judgment may become a lien on real estate only upon the judgment creditor's affirmative act of recording a Memorandum; therefore, it is within his power and control to refrain from recording so that his judgment does not become a lien on real estate. If the defendant or any holder of the contract were able to obtain a Memorandum of Judgment which was then recorded in the appropriate office so as to create a lien on real estate, the judgment debtor clearly has adequate remedies to clear title and recover damages from the holder for breach of contract. Negative covenants are as valid and enforceable in Illinois as other kinds of contract terms assuming that they do not violate the public policy of the State. Canfield v. Spear, 44 Ill.2d 49, 254 N.E.2d 433 (1969), upholding and enforcing a covenant not to compete; Smithereen Co. v. Renfroe, 325 Ill.App. 229, 59 N.E.2d 545 (1st Dist. 1945), upholding a covenant not to use trade secrets; Paschen v. Pashkow, 63 Ill.App.2d 56, 211 N.E.2d 576 (1st Dist. 1965), enforcing a covenant restricting a real estate development to single family residences. We believe that were the holder of the contract to violate or threaten or be about to violate the covenant of waiver in this contract, the judgment debtor could go into an appropriate state court to seek injunctive relief to prevent such action or to clear his title.