How Many Years Do Postal Stamps Stay Sticky?

I am thinking of stocking up on forever postage stamps before the rate increase but don’t want to end up having to stick stamps on envelopes with glue.

Do you mean the self-stick kind? Or the ones you have to lick?

I still have some of both kinds from at least 10 years ago.
The self-stick ones just go on sticking.
The lick ones seem to work, but I get nervous.

Self-stick.

That glue is actually ‘press to stick’. Because the glue is sealed inside little bubbles; it’s only when you press them down & break the bubbles that it is exposed to air and will dry out. So they should last for years.

I have some address labels, old enough that they are on pin-feed carriers, must be from around 1996, and they still work. They are just recently losing a bit of their stickiness; I use them for name tags, and they tend to only stick (to clothes) for an hour or so.

They say “forever.” If they don’t work in a billion years, take them back to the USPS and demand a refund.