Widely debated. Two general schools of thought.
1) They are the best thing since sliced bread and everyone in the world needs one!
2) Complete waste of money and energy.
I'm 90% in school 2, but I'll say that they have a function. Emergency fixes for green water and assisting ich medicine. But 24/7? Absolutely not. In a healthy and well regulated tank, they are not necessary. I am one of a few who believe they may actually kill beneficial organisms as well as algae and parasites. Ultimately it's up to you, and you'll get very strong opinions either way. But if you dcide you need one, I'd challenge you to wait a while and see how much you really need it. With proper care and quarantine, rarely will a uv
-fixable issue arise. But if one does, you may be pleased to have it available.
Long winded, I know. Sorry! Lol