I have built and repaired quite a few and never had any smoke occur.
Because.... you are EXPERIENCED
The point I was making is someone with ZERO experience either building or repairing computers, like in this instance the OP's 15yr old son.
If you buy a prebuilt any old numpty could have assembled it and you won`t know exactly what is in there.
Build your own and you know exactly whats going on.
"Any old numpty", which would be like every other factory or business worker on the planet,
As to knowing whats in it, thats a simple case of reading the description isnt it ?
But what you are implying is if someone, without experience is going to build their own, there must be some magical transfer of information to tell them that this motherboard is better than this other motherboard, or that this power supply is adequate for the power draw of their system,GPU etc or even what GPU they should choose, or even for that matter whether they should use intel or AMD
Whats the differences ? as in why would someone choose AMD Ryzen over Intel i3,5 or 9
BITD AMD was known because it runs hot, I believe its still the case. So maybe not the best choice for a gaming system that it going to be running at max.
Which then leads to another point. Should they use standard cooling with a gaming system, or is liquid cooled more use, in relation to using intel or AMD.
And thats just a couple of little points, that anyone aged 15 is not going to know without a lot of research. So again theres no magical transfer of knowledge just because a person has decided to build rather than buy.
It's a long time since I built my first system, which i think was a pentium 2 or 3. I think i had either 256 or 512, though probably 256mb ram and a really basic gpu- integrated i seem to remember.
But while its ok, i wouldnt recommend it as a first system unless you are actually into that sort off thing from the off.
So i believe it would be best for the OP's son to get a system, and maybe later upgrade the ram, the gpu but only if he is interested and looking to get into that sort of thing.