[Remastered] Newbie question: what are the leveling and looting precautions?

I've heard about the original Oblivion having the worst leveling dynamic ever and that it was fixed in this remastered version, but i think there are still precautions besides not leveling too much without leveling combat skills. I'll put my questions in topics so it is easier to answer:

1. Equipment loot scales with player level, so i should let the Oblivion Portals for higher levels (so i can take better loot)? Or do the portals recover? Do they appear randomly?

2. Unique quest equipments have their status based on the level i completed the quest so i have to get them when i'm at a high level?

3. Is there a minimum level to get every quest item at its best or they scale until max level?