I used to try and cover everything before they left latest but now I’m much more selective because I focus more on performance now over being a completionist.
If you aren’t a player that needs to have everything fully covered and go for characters that will complement your current roster and playstyle, I would save your cp for special stores where there is a character that will fill a gap in your roster or augment your main team where their skills could come in handy during everyday play. There are obviously the meta characters that everyone has or should have that will carry you for awhile in both pvp and pve where your continued performance over time will allow you to obtain/hoard more resources for future must-have releases. These special stores are also probably the best bang for the buck if you are trying to finish them out or level them higher. New release CP stores are also a good avenue to try and nab the one cover you might need for the 5* essential nodes in pve.
As for LL, I am just saving them until a new character(s) comes along that is a significant improvement over my current pve and pvp team comps. If the character will not improve my game in any meaningful way, I won’t pull for them. My situation might be different than yours because I have competitive meta teams already rostered, so ymmv.
As for cp/LL hoarding strats, I do tend to change my TH on the fly to focus on getting cp and LL champ rewards first over 5* feeders, unless the resulting cover will provide 25 CP or a meta. One TH per * tier, and my priority order is :
5* - meta I want leveled higher
4* - CP (odd levels, level 330 and up), then LT
3* - levels 260 & 246, then levels 226, 238, 256
For me, CP > LT always, since CP can be used for both LL and special release stores. You don’t really want to be caught with low CP on hand if they decide to randomly release a really good store.
I pull all covers but LL btw, just for the chance to earn shards for targeted heroes that will net me CP.
Not having a character fully covered isn’t the end of the world, especially once you have your go-to team(s) that can perform in both pvp and pve. My personal viewpoint is that if I’m going to hoard, I just want to make sure that all the time and effort I spent in accumulating all of those resources and then spending them is going to have a measurable effect on my gameplay. If obtaining a new character results in just a marginal increase in my performance, then I just skip and continue to hoard.