Daddy longlegs are known to live for 6 months to 3 years depending on the species. The term "daddy longlegs" has been used to refer to the species Crossopriza lyoni, which are not actually spiders, and to Pholcus phalangioides spiders.
Crossopriza lyoni are not spiders at all, but rather belong to a totally different species called Opiliones. These creatures lack two features that would make them actual spiders: They cannot spin webs, and they do not have fangs to inject venom.
Even though Crossopriza lyoni is not a spider, it is still considered to be a cellar spider along with the Pholcus phalangioides. This is because both species swarm and cluster in dark, dank and moist man-made structures. Both species are synanthropic, which means that they prefer to live within or in close proximity to human dwellings.
The Crossopriza lyoni hatchlings will become a full-grown daddy longlegs in 80 days. These daddy longlegs species can live from 6 months to 2 years. Pholcus phalangioides eggs take 9 days to hatch, and they can live up to 3 years.