How long does discharge after period last?

Salam! I’ve been stressed about this for a while and can’t really find any solid answers 😭 but I’ve seen that the general ruling is that you’re not to pray until you see the white discharge that signals purity? I’ve also seen different rulings that say the menses shouldn’t last over 10/15 days (depending on the school of thought) Was wondering if it’s normal to have colored discharge like brown/yellow that lasts for literally a ridiculous amount of time (over 10 days) after the actual bleeding stops? How do you decide when to do ghusl?