No, there is no hard-and-fast length of time; unless there is an employment contract or other written agreement delineating a period of time for reimbursement, their only obligation is to do so in a "reasonable" time. Several months is  most likely not reasonable; based on what you write, the reimbursement is past due. Unfortunately for you, if they just will not provide it, the only way to force them to provide it is to sue them (e.g. in small claims court, as your own attorney or "pro se" to save money). Suing an employer is clearly a drastic step: if it's a small amount of money, your wife may wish to effectively "write if off"--if she gets it, grate, but otherwise give up on it, rather then sue. If it's not small amount, if your wife expects or is trying to get a different job, she may wish to wait for a few more months, then sue only after she leaves.