Haven gotten this knowledge, I started fixing damage home appliances in the house e.g. the wall socket, lamp holder, broken wires in an Iron etc. My siblings started calling me electrician, mum would call me engineer...Smiles
I come to realise that there is no end to knowledge. The knowledge you derived from physics has really helped you and your mother's business.
Acquiring the knowledge might look so difficult but with persistent and constant eagerness, there will be nothing impossible to achieve.
Thanks for sharing your experience.