I'm thinking of making software add-in in VBA for MS Excel.
I will 'rent' this add-ins out and send my clients a new license-code every
month after the bills are paid.
This license-code is (at least now in the beginning) planned to be emailed
over in txt files (which the client has to store in their "My Documents").
Inside the file, with the name "license-code.txt" a license-code like
dk3-3kk-555-777 would be found.

So to have this license-code being 'useful' I need to program a function
which check whether the valid license-code is in place or not (toward
current month).
I plan to put in the function enough license-codes to cover the next 10
years, so the total of text-code which needs to be searched will be 10 x 12
months = 120 license-codes.

Now we are at the core of my question: Will this way of doing the licence
check result in a slow working code (I assume Select case will be used)?

(- anyone who have samples of such code?) Thanks, JohS