Introduction: I am not certified in anything, except phlebotomy. I do limited repairs: some plumbing, electrical, structural, etc. I used to work as an apartment maintenance person for years. I can tell when people specialized in a particular repair are needed.
I can do many things, i.e. cleanout an A/C but do not work on the Freon pipes or compressors. I can change a light fixture but to change a breaker, certified persons are needed anyway.