Lucky/Cosmetic Box Question

I've been really appreciating the free lucky and cosmetic boxes when i get them, ive been playing everyday for a couple months now and ive been getting a lucky box once a day, cosmetic usually every other day, a few days ago it stopped rewarding me even though i havent stopped playing (the same routine) since i got back in. I was just wondering if there is a cap on the amount you redeem? or is it free every couple days? either way i appreciate it, free items are free items. the concept alone is really cool whether you buy coins or not.

TLDR: what are the requisites to earning free item and cosmetic boxes?

It's a part of our Activity Points system;

For every day you actively play in the game (minimum 3 hours and 500k exp), you will receive a free Lucky Box! The more days you play in a row, the greater the rewards:
Every day you will receive a lucky box.
+ One box of cosmetics every 3 days.
+ 1 AP Shield every 7 days.
+ 100 coins every 10 days.
You are also getting bonuses from EXP (+10% per day) up to +100% (after 10 days).

I checked your account and some days (16th and 18th) you played less than 3 hours, which is why you didn't get the activity point and the reward.

thank you guys for the clarification, i appreciate the help and also appreciate keeping the dream alive. Very reasonable requisites especially for free items. All is appreciated. Thanks again.