every rebate is good, so you should always save power items to do max rebate rewards (some of the rebates need an update but yeah they're still better than nothing), best events to spend coupons on, are the events where you can get back some kind of compensation like milestones rewards or power goodies for example, lucky board, great plates, konoha great tree sry if im missing some

Good rebate events, most are at what you do is you save those resources to certain numbers to get the most out of it.

Cave keys: 1050 or 2100

Refines: 500

Charms: 500

Battle armor: just do as much as you can when the event is happening.

All other rebate events it doesn't matter.

Best events to spend coupons are the ones with both an rng portion and a shop. So best ones are lucky board, lucky stars wheel, and konoha great tree. Other decent ones are fireworks event, great plates to a certain extent, wheel of fortune is okay, and mission mobilization. All other ones are only worth it if you really want a specific item. And also remember to not spend unless you can get the maximum rebate from a fukurokumaru deals (or at least a complete ninja)

Refine 1400 for 7-10.

It might be a lot for many players but cheaper than 500 rebate in long run.

You do know how long it takes to get 1400 advanced refines? Putting it mildly would be almost half a year. And in that time, your p1 is going to fall so far behind its not worth it.

Your p1 will "fall behind" approximately 660 secondary stats asuming 100% purification for the time of saving. Thats not as much as you think. Also you get ahead of the curve because in the long run you get more refines than those using x500 rebates.

Refines are far from efficient nowadays, its better to invest in training potions or any myoboku, no matter what levels you are at in those features.

Took me 3-4 months. and I'm not at top 3 anymore. So many rising stars these days o_O