I'm designing a simple application (an OS X Dashboard widget, in this case) which the user might use multiple times a day, or hardly ever. When it detects that a newer version is available, I intend to display a small dialog asking them what they want to do about it. For example:
Version 1.1 is now available; you have 1.0.
If the user clicks "Later", they'll be reminded again after X amount of time has elapsed. My question is: how much later should "later" be? 5 days? 10? 15? A month? I imagine the answer might vary between different kinds of applications.