I recommend to check varroa every month and a half (every 45-50 days). And then do the treatment if needed.
Varroa Mite check
Honey B Healthy
Helps Promote Healthy, Vigorous Hives.
Add to your feeding mix to help build up packages, nucs, and swarms.
Vented Beekeeping Jacket
A good vented jacket is very important especially here in CA.
I recommend this jacket
The Backyard Beekeeper
An excellent introduction to small scale Beekeeping.