As it currently stands in Paragon, each hero has a nifty mastery progression that allows them to level from 1 to 10 and earn some decent rewards along the way.
When update v42 goes live in the near future, they’re squashing that ten level progression, allowing you to gain those precious chests a bit faster, and then once you do hit level ten, you’ll be able to prestige and start the cycle all over again.
With changes to progression come changes to rewards. Prestiging will grant you multiple levels of crowns, in addition to rival skins, emotes, and banners.
But there are some changes you need to be aware of going into the patch so you can prepare accordingly. Firstly, any progress on masteries you don’t own will be lost. So if you’ve made a decent amount of progress on one of the heroes with an unowned mastery, grab it now or lose your progress. On the plus side, there will be retroactive rewards on masteries you do own. So stock up.
Also, if you have any chests you have yet to open, then you might want to consider opening them now rather than after the patch as the chest contents are changing. Chests after v42 will no longer have small coin drops or reputation. So if either of those interest you, open them now. Post-patch chests will have Cards and Gems if those tickle your fancy.
Read more about the changes over here.