If one is having ongoing parasite problems I'd first want to figure out the cause, fix that, and then worry about treating the symptoms.
BTW any advice I give is what I DO, not what I've read

No slam on anybody here but I've seen many instances of people repeating what they've heard or read... for what it's worth I only offer up what I do that works for me (or doesn't work as the case may be.)
If there are ongoing issues with parasites, first look at the source of your fish - are you inadvertantly buying sick fish? Quarantine *should* be standard practice for hobbyists but I live in the real world and I know that most people don't. So having said that, be sure of your sources.
If the fish are becoming sick after entering your care, examine your system for possible stressors - aggression from other fishes, insufficient quiet/dark time at night, possible stray voltage, water quality, diet and other factors can stress a fish to the point of succumbing to illness.
UV and medications are "band-aid" solutions. Fix the actual cause and you shouldn't have any more problems.
HTH
Jenn