Don't worry about them losing flavor at all. Unless your storage is very high in humidity & temperature (70 or higher for rh & temp) My guess is you won't have the patience to lay off of them before the storage would start to negatively effect em.
Things to make sure of... Don't store any "flavored" cigars in the same humidor.
Don't open the box on a regular basis (ideally never but if checking for beetles, as sporatically as possible)
Dont' break the bundle. supposedly 49 instead of 50 has a negative effect. Don't knwo 1st hand knowledge on this one myself, sorry.
If you're sincerely concerned, wrap your box with plastic wrap or keep them in "food storage" quality zipper bags. This will slow the aging process down & ensure a smoke that will last for much longer if the conditions above are followed.
Something to remember, if you break the box, have bad storage open it daily & don't keep em in a bag, I would still think you have at least 5 years before they're completely gone.
PS - Mild or medium doesn't mean a cigar won't age. When you're thinking of rules for Cuban cigars more often than not you need to forget the lies you learned when you smoked N/C's. Cigar Aficionado does more for propaganda than Jane Fonda ever did!