I'm not that precise with my UV source to notice one bulb flaking a bit.
Anecdotally, they sometimes do come up to full output at different rates ( between say 2 and 10 seconds). Over a 30-60 minute exposure that is no big deal.
For me Alt process is about printing while there are other things also to do, particularly cyanotypes.
Size the paper in advance. Make enlarged negs in advance.
Coat the paper once home from work and hang to dry (I coat with a variant of the glass rod method, and find the print paper with sensitizer dries in under half an hour, if hung up.)
After dinner, paper is ready. Mount the neg and paper in the contact frame, fire it into UV box. Set the timer for 20 minutes. Do other things; make up tomorrows lunch bags, supervise homework, sort laundry, etc. Check at 20 minutes; almost always it needs at least half a stop of more exposure, so come back in another 10 minutes.
Once ready, dump in the sink, dribble fresh water into a tray to wash and clear it. Clean the dryer lint trap, check if fabric softener and laundry liquid are getting low... it is the most relaxing way to print.