I've worked electrician,plumber and HVAC trades. Electrician paid the best and is the one I finally retired from. Here is a tip, don't just learn one. The last job I had was top civilian electrician at a military base, after working there a while I was chatting with the boss and he asked if I knew why I got the job. I told him no. He said others had the same qualifications as electricians as I had but no else had a EPA Universal Refrigerant certification. The base HVAC tech had just quit and they hired me to cover two jobs till they could hire another HVAC tech.