Provided you have good eyesight and steady hands, I've mostly found what happens as you get smaller is:

- Heating becomes easier. There's no large sinks to take the heat away. It's also easier to overheat things.

- You need finer tweezers, and don't drop them because if you do the tips will bend.

- The solder's surface tension does more of the work. It feels a lot more like sticking together things with tiny droplets of glue. Having the correct amount of solder in the right place is critical.

- Solder and flux become two separate things you have to care about individually

- It is easier to burn yourself

- learning how to brace your hand against something in a way that gives you very fine control. One reason soldering with an iron can be difficult is because your hand is so far away from the tip, like trying to write with a pen held by the end.

It's great for working on vintage equipment, stuff that might need (and warrant) that kind of repair. Less so if you run a cell phone repair shop.

I don't think that modern boards are really repairable at all beyond component replacement- 4+ layer stackups being the big reason. If there's a way to do anything to those boards besides total replacement I'd be super interested to know.

The techniques here are also way beyond basics I think- like, you look at most guides for repair and it's "idk just solder some bodge wires on there, here's what a good joint should look like"

> The solder's surface tension does more of the work. It feels a lot more like sticking together things with tiny droplets of glue. Having the correct amount of solder in the right place is critical.

I believe this is why I have an easier time hand-soldering BGA than QF[np]: I can't screw up solder amount/evenness.

When I started my first job a coworker encouraged me to learn how to solder SMDs and do "microsoldering". Like most people I thought I was going to need high precision and a much steadier hand. Probably like most people that learned I was impressed at how quick I picked it up. I think the hardest thing was learning about part "tombstoning" but that's not that difficult to deal with. I'm not going to say it is easier than soldering through-hole components, but I think for most people the mental barrier is much higher than the actual barrier.

I now highly recommend learning it to anyone doing electronics. It's well worth the (small) time investment and makes things a lot easier, opening lots of doors. Even for a hobbyist you immediately get benefits. Everything becomes more compact, 2 sided boards are much more usable, and, of course, it opens up a lot of repairability (and recycling. Are you really a hobbyist if you aren't desoldering and reclaiming parts?).

Andrew Zonenberg posted a Twitter thread a year or two ago where he fixed a missing PCB trace some layers down a PCB, with a stereo microscope, precision mill and very steady hands.

Edit: here's the thread. It's a 6 layer PCB with a short on L5 that needs to be fixed from the L1 side.

https://xcancel.com/azonenberg/status/1468825231225540611#m

> Are you really a hobbyist if you aren't desoldering and reclaiming parts?

Fun memory from who-knows-how-many years ago:

While installing a Playstation mod chip, I managed to overheat a nearby surface mount resistor, pulling off one of its metal contacts in the process. I didn't think that was fixable, and since it was Sunday, the local electronics shop was closed. I ended up disassembling an old junk digital camera that hadn't yet been taken to the e-waste recycling drop, and finding inside it a resistor that seemed close enough to maybe work. The transplant was a success, and the Playstation ran great thereafter. Very satisfying.