I don't use a trickle charger, so will leave that question for others.
I don't check my engine battery, but check the water levels in my house batteries monthly. Well, usually I do - it's been two months right now
I'm very diligent about it when in drier climates and usually diligent when not. Will do it before pulling out of here in the next couple weeks. Recommendation - monthly.
Something else I recommend that isn't mentioned often: Check your roof monthly also and anytime you're parked under lots of trees. You never know what might be up there, and a small branch that falls on the roof and you don't remove, can cause damage to the roof or the ac cover, or any other cover, etc.
Beth
“Dare to live the life you have dreamed for yourself. Go forward and make your dreams come true.” ~ Ralph Waldo Emerson ~
"He who treasures the small things in life has found the path to true happiness"