I would only use it if they, put simply, do not sign ttm or vv

Many times the older actors/actresses don't have agencies anymore and the mail goes right to their homes. It's fine to write to them there.

On occasion I have found a personal address and used it, but won't put it here for the public to see.

I would say bad idea, unless they don't have an agent or manager that you can send to. But that's just me; I'm curious to learn what others think.

Does anyone have any opinions on sending autographs to a celebrities house, if you have the address? Would you say its generally a good or bad idea?