Tips needed for upgrading survivors
All my survivors are level 20. The level I need to get to before being able to train them again jumped by A LOT. I think it was something like going fron level 52 to 59. I just barely got to 57 and that's taken me MONTHS. That it can take 1 or 2 days to upgrade a building without spending gold seems ridiculous since it takes enough time already just to accumulate the millions in food or experience points. At lower levels you just needed to get through 3-4 levels before training up your survivors again. Is there a better or faster way I'm just missing? Any tips are appreciated!