I more or less had my strings sorted out as a teenager, probably the same way Aaron and most other people did. I assume the next thing will be someone making a video about how I'm using the wrong picks too. [I'm sure it already exists, don't link me.] I've seen a couple of that guy's videos and he's okay, and I kind of wish I had all these resources when I was a kid learning, but then again I spent most of my free time actually playing. I probably had a dozen gigs played before I knew about aftermarket pickups--
--Incidentally, I learned some of my general gear knowledge early on from a snobby little gear dweeb who paraded around his LP Standard and Marshall at all of the school events and music classes. All the cool gear, lots of stories about his band when he lived in another state, but couldn't get in one at our school since he couldn't really play any actual "songs," (remember those pesky things that you need to learn, besides the intro or cool riff part?). I bet he's out there somewhere in the YouTube comments hot on this string subject right now--
Anyway, strings. My experience says you buy a bunch, play them a bunch, it will work itself out. They're cheap and disposable enough. I mostly default to 10-52 at Fender scale nowadays, they just feel right and let me hit them in a certain way that lighter strings don't, but I but have a multiple guitars set up certain ways I like. I will put a 56 low on in a couple recording scenarios for a thing I do. A nice shreddy Ibanez I have 9s on hand in Eb tuning for another example. A barely-touched Schecter drop tuned with 12-60 DDTs on it.
Acoustics are another case, I won't go lower than 11-52s, and 12s for recording anything. Maybe it's me, maybe my guitar, recording equipment or techniques, I don't know. But yes that matters.