In my 20 years as a nail tech I have learned not all UV bulbs perform equally. In my 17 years as an instructor I have also learned the length of time UV bulbs are good for changes based not only on how many clients one currently has, but also on how long each tech has their lights on for during a fill. (and this can change throughout ones career as we become more proficient and run our lights for fewer cures per client.)
These are the only bulbs I use now are these specific bulbs :

I only use these because I have found they provide:
1) the deepest cure
2) the hardest cure
3) they bond gel products to the nail the best &
4) they get more longevity than any other UV bulb.
With a client base of 80, I change my bulbs in November & May. This way:
1) I never forget
2) I get better gel performance (less cracking & lifting) thru the summer months as clients start gardening or going longer between fillz
3) I get better gel performance thru the winter when clients need a stronger cure because the cold weather makes gel more brittle & winter vacation clients may go longer between fillz
There are so many factors that contribute to our success as a nail tech, and the type & condition of our UV bulbs & lamps are part of the success equation.
~Avry Bablitz
Catalyzt of Tranzformation
Nail Innovationz