Question about quest's

I never seem to have the time to practice fighting, or learn skills, trade, repair etc in between quests because I’m always being rushed to the next objective. A lot of times if I take a simple detour to go buy some potions or sell something, it gives me a failed quest. I hate this. How do I know which quests are on a timer? How do I know how long I have to get there? How am I supposed to buy/sell, practice if the quests are all connected to each other and I’m constantly being prompted to “hurry before something bad happens”. It’s driving me nuts because I just want to take a break in between the main quests and start working on some skills but I don’t want to fail quests. I want a definitive way to tell if a quest is on a timer, because if I just use my gut, they all are. I’m always being told to hurry up.

There is plenty of time if you just stop taking new quests on haste, mate.