Electrolysis takes between 9 months and 18 months. Average is about 12. This is identical to how long laser is supposed to take. The time is dictated by yearly hair growth cycles, just like with any form of permanent hair removal.
The hard part is the first full clearance (which can take many hours, but should be completed as soon as possible). Once you’re fully cleared then the rest is easy. Just pop in for an hour every week or two to treat any new hairs that pop up. At about month 6, you will probably only need 30 minutes every few weeks to treat the little bits of new growth. Toward the end of the year, you may just be getting a few minutes of treatment a month. Since the hairs are removed one at a time, the number of hours you will need to invest will depend on how many hairs you have. But most of these hours are invested at the very beginning, and even with TONS of hair on a large area, it will still take only about 12 months.
Spend 5 or 10 hours getting a full clearance on your back one time (in a marathon session, or spread over a week or two), and even if you never went back for touch-ups throughout the year, you’d still have significant results (probably 25%). Pro treatment is $60-$100 per hour, so once you get past that first expensive clearance, all the follow-up treatments are pretty easily to slide into a monthly budget.
Some electrologists who work reeeally fast (like James and Josefa), are very confident that they are faster and even cheaper than laser. But most electrolysis is a little more expensive than the equivalent laser treatments. The length of time is about a year with both laser AND electrolysis though. So if that’s what’s holding you back, definitely go for it.
For what it’s worth, many many many men have their back done with electrolysis. So it’s not like it’s really difficult to do.