I've never heard of such advice and from my experience I don't think it's very useful. As you mentioned, every position is different, trading down pieces is usually called for when you're 1. at a material advantage 2. at an initiative disadvantage, or both. So trade down when you're ahead in material or being attacked so your opponent has less attacking pieces and your material advantage will be more potent.
For a general rule, the idea of "to take is a mistake" is a good starting point. Most beginners trade as many pieces as possible so that they can't blunder them. This sounds like a good idea but when you trade on your opponent's terms (without purpose) then you're only helping them develop. You should aim to develop and offering even trades is fine, but you should be reluctant to be the one accepting trades without provocation.
Here's an example in the scotch opening:
Hope this is helps, if anything is unclear, feel free to let me know!
I Heard this from a YouTuber where he said’ “As beginner when you playing as black you should try to trade as much pieces as you can since you are already at a disadvantage because you mostly responding to whites moves,”
So should a trade my pieces or guard them,
I know it depends on positional, sacrifices and tactics all this “big words” is just a bit overwhelming for us as a beginner because all we can see is one ahead not three or four moves ahead, we cant just says “takes takes takes then takes and then my opponent will at a big disadvantage/ mate”
The question must be confusing for some of you so don’t judge i was also confused while writing it down since it didn't make sense to me.
Thanks.