At what point in a renovation would you have the electrician, for example, giving the estimate?

GC would hire electricians etc and I presume they would be licensed also, I can demand it in our contract also I suppose. 

, the appliances/furnaces are still under warranty and I have people to call if I do have an issue (plumber, HVAC guy, electrician and a general handyman).

We have an excellent electrician and plumber.

I am not overly-handy (I never owned tools until I bought a duplex) - so far I've done basic electric (installing an outlet, adding a junction box, putting in receptacles, removing breakers, fixing a 3 way switch -- all things an electrician wouldn't touch -- or would charge a couple hundred bucks to do, cost me about 7 dollars - literally), replaced an exterior door, removed rotten siding and put up new siding along with replacing the plywood behind it, re-built the rotten framing of a garage wall, installed a ceiling fan, and just about a thousand other things along the way.

And an electrician's license takes time to achieve, you may reconsider and get a contractor's license.

I know some Landlords that establish a good relationship with a trusted electrician, plumber, etc.

@HAILEY ERSKINE Good for you, get the ducks in the row, start collecting 1) realtor, 2) real estate attorney, 3) cheap title search, 4) CPA, 5) Contractors (handymen, electricians, plumbers, roofers), 6) Insurance. 

My electrician strung me out for months and cost me thousands in mortgage payments, plus lost months rent.

Electricians, Plumbers and Elevator repair all require apprenticeship.