Field w/ value list vs. ad hoc entry

[ken_s2007]

I have a personal inventory database, and have a value list "vendor" attached to the vendor field. I pop it up and create a new entry any time I have a new vendor whom I think I might use again (for speed and accuracy of entry). But if I buy something from a vendor I doubt I'll ever purchase from again, I enter the name ad hoc (I don't enter it in the value list).

Is there any best practice on this sort of thing? thanks

Ken