Common house spiders typically live 1-2 years indoors, with females outlasting males. Some species push to 3-7 years if conditions are ideal—no predators, steady food. Your window buddy's beating the odds at 2+ years. Keep feeding it flies!

For clarity, I am being conservative by saying 2 years... my wife believes he's been there for 5.

Only one way to find out: capture a few, breed them, and study their offspring.

Do people still say "for science!"? if so, that.