I can't see any information on the lifespan of an Intellect Devourer in the 5th edition of D&D monster manuals. Is there any information that says or hints in other sources/books, including past editions, as to how many years an Intellect Devourer can live for?
I don't think we know
As far as I'm aware, the lifespan of intellect devourers is never given. This is the case for a lot of monsters in D&D as the lifespan is rarely relevant to gameplay or even story. If it is relevant to your game, I would leverage the same lifespan as mind flayers since they are created using the same process (ceramorphosis): avearge of 125 years.
Intellect Devourers can eventually metamorphose (in 4th edition at least)
In 4th edition (in the Monster Manual 3), intellect devourers can grow into wolf-sized creatures called intellect predators and eventually metamorphose into intellect gluttons:
As adults (intellect predators), they are more akin to wolves, hunting in packs or serving more intelligent creatures as guard beasts. Those rare few that survive long enough metamorphose a second time, becoming the truly monstrous intellect gluttons, which are also called brain collectors.
That said, there is no mention of how old an intellect devourer needs be before growing to this size, or metamorphosing.
All that said, 4th edition lore for these creatures are a departure from their original lore and none of this is mentioned in 5th edition, so it is unclear if this is still considered to be accurate.