[@Muttonhawk]

If we cap rebuilding at 2x the original cost, then the repayment time is 4 Turns. If you keep accumulating Might, you would have enough Might to upgrade that Holy Site to double that cost after 2 more Turns. Without some other cap, this strategy allows exponential growth with a doubling time of 6 Turns.

(For comparison, a 3x cap makes the repayment time 3 Turns. Anything more makes the repayment time 2-and-a-bit Turns.)

If we put a time limit on how often you can repair a Holy Site, then it would need to be longer than 6 Turns to be effective at minimising abuse.

However, we also need to remember the original purpose of repairing Holy Sites- not to upgrade them, but to fix them if some IC event destroys them. If we make the time limit too long, then it can interfere with this process. If we tie repairing Holy Sites to the creating new Holy Sites timer, this would also interfere with the ability of a character to legitimately repair a destroyed Holy Site.

If our concern is people abusing the system to gain more power, I have a fairly robust and simple solution. Cap the amount by which a Holy Site can be upgraded/repaired to 2x the original cost, measured against when the Holy Site was first built. This prevents the exponential growth scenario, isn't too overpowered so as to not encourage it too much, while still allowing people some room to renovate existing Holy Sites and repair them whenever necessary.