If you live in Temecula, you already know what the water here does to a coffee maker. Now picture that same scale building up inside your drain lines, along with the grease and soap of daily life, year after year. When your drain clogs, gets snaked, and clogs again a few months later, this is what's happening. The snake made a hole. The buildup lining the pipe, and hard water contributes plenty, stayed put and closed it right back up.
Hydro jetting descales the pipe the way you'd descale that coffee maker. A high pressure stream of water scrubs the inside of the line all the way around. Grease, soap and mineral scale get stripped off and flushed out instead of tunneled through.
Is jetting always the answer? No, and you'll be told so when it isn't. Some clogs are one time events that a snake fully handles. The contractor looks at what your line is actually doing, explains it in plain English, and gives a recommendation. You make the call from there.