Spending units
I started an account a little over a year ago but had to stop fairly quickly due to a family emergency. I picked the game back up a few months ago and have quickly been growing my roster. Sadly, I didn't hear about brackets until after I had put enough time into this to make me not want to restart, so my growth is happening without winning champs from arenas. After 3-4 months, I have 25 4*, but only 2 duped (beast and miles).
The question I have is where I should put units as they accumulate. I have a few carb cores in waiting, and it'll be a while until I gain enough levels to even really use them. For this reason I'm unsure if using on masteries makes sense. I can save for masteries, save for eventual arena grinds or event runs, or use on deals. If I use on deals, what type....4/5 star crystals/shards, catalysts, limited time heroes (like og vision), awakening gems, sig stones, etc.
Any advice would be greatly appreciated