I learned how to climb on a singing tree rope runner and SRT. I learned a few of knots, bought a big shot and throwline and practiced with a base tie at about 10-15 feet til I got comfortable. Then I went higher. I very much learned on the job, which probably wasn’t the smartest way, I was removing a decent sized maple on my 4th or 5th climb ever. I came from working as a contracted timber cutter full time for 3 years so I did have saw experience. I did 3-4 removals and several trim jobs before I ever owned a set of spurs, which made trusting my spurs difficult for a long time. I would learn to trust those spurs low and slow first, I did not take the time to do this and learned spurs while working. I much prefer Single rope over double rope. 90% of my climbing is done with single rope. I’ve always used mechanical multicenders and never hitches. I have a larger arsenal now days with a few options, I’d like to add a hitch climber and start climbing on hitches, but it’s just something I never learned in the beginning. Mechanicals you have to watch side loading on limbs, getting a twig jammed into them, etc, so that’s something to consider when looking at them over hitches. If I climbed pine a like, pitch and how a device reacted to sap and pitch would be a large deciding factor.
I had a steel core and rope lanyard when I first started, and I climbed with both, and a primary tie in. Now I only climb with 1 rope lanyard and my primary. I don’t like steel core, because you can’t inspect them, and I just prefer the feel of rope. For a tie in knot, I use a bowline with a stopper, or more often, I use an alpine butterfly with the tail and working line on the ground so that it is retrievable from the ground. You can either use a pinto pulley to connect them without sideloading a biner, a quickie, 2 steel carabiners, or feed the working end of your line down through your knot and have no hardware, and still have a ground retrievable tie in. If I’m working a spar or conifer where I’m cutting as I climb, I just cinch a running bowline on the spar and lanyard and spur up the tree, or climb with my zigzag around the stem. With the zigzag around the stem, you do not have a fast bail out method unless you use a limb as a natural crotch.
That went on for a while and hopefully you can make sense of some of my gibberish. I certainly don’t do everything right and I’m learning as I go but that’s the way I got started and so far I have never had a real “ohshit” moment.
Biggest thing is inspect whatever you buy, inspect it like your life depends on it. Because it does