What many people don't keep in mind is that plants are usually sold in way-too-small plant pots - they usually need to be repotted immediately and can use some fresh soil, optionally fitted with some kind of plant-benefical nutrient.

What you mention is definitely true, but from my experience, a lot of my friends' and acquaintances' plants die because they don't repot them.

Also a lot of plante usw the Winter to shed a lot of foliage even indoors

Personally, I ain't got time for any plant that doesn't grow like weeds. My spiderplants survived month-long dry spells and they're still multiplying!