My house already age more thna 40 years old. Build around 1970.

I got an issue where certain room has tripping issue. I suspect there is an wiring issue. Question should I replace all wiring... Or just replace wiring that got problem only?

I don't want do wiring all area because my house sudah banyak deco. I concern it will disturb all the deco. Is there where people can minimise the defect

Or should I seperate the main panel into 3 different panel for kitchen and upstairs. So I can safe cost?

what the difference with db and sub db