Core problem: You cannot max every Tarstone on one save. Tarcores only come from tempering other Tarstones, L2 to L3 costs 6 Tarcores, and the net economy caps you at roughly 25 maxed stones out of about 73-75. Players who dump cores into "maybe later" stones lock themselves out of the build they actually want. The question is not how to click upgrade, it is how to not waste a finite resource.

1How the Tarcore Economy Works

L1 to L2
10,000 XP + 100 coins
Produces 1 Tarcore. This is the cheap farm tier.
L2 to L3
20,000 XP + 6 Tarcores
Produces 3 Tarcores back. Net cost: 3 cores per max.
Save Cap
~25 L3 stones
If you L2 every stone then spend cores on maxes. NG+ does not restock cores.
NG+ does not restock cores from old chests. You keep what you already generated. Plan the 25 maxes across the whole save, not per cycle.

2The Tarcore Farm Loop

Farm XP, not extra cores. Cores are not an enemy drop. Dense packs and strong enemies while 10 stones are slotted is the entire loop. Night mode and extra exploration are what players use when story routing is done.

3Which Stones to Keep (Decide by Weapon Lock)

Many stones only fit specific weapons. Maxing a stone that does not fit your main weapon is a permanent waste on that file. Pick keepers by weapon lock, not by flavor text.

Only max a stone if it is on the weapon and shell you will finish the game with, and the L3 text is the reason you equipped it. Anything else is a permanent waste on that file.

Common Mistakes to Avoid