Completed rows of stickers earn you battle points.
Complete 1 row = 1000BP
Complete 5 row = 3000BP
Complete 10 row = 5000BP
Complete 30 row = 7000BP
How do you get stickers?
Rewards as part of the battle pass, purchase them from the dota store or on the steam community market (there's a convenient link your sticker collection.
What do the stickers do?
Nothing really. You can 'stick' them to your favourite heroes or showcase some of them on your profile.
Where are they?
Part 1 of the BP and part of the menu on the left hand side.
How many sticker rows should I complete?
How many do you need for the next big reward? There's diminishing returns on the rewards too so you might want to stop at a certain tier (I plan to do 10 rows of stickers but not 30). Also economically speaking it's a pretty good 'deal' if you just need a few levels. Roughly 0.06-0.10 cents on the market for each sticker, 5 stickers for each row. You can do the dota math to figure out if it makes sense for you.
Source: https://www.reddit.com/r/DotA2/comments/zsss2z/battle_pass_2022_a_few_levels_away_from_the_next/
