What if you suddenly unlock a unit (or maybe a shop comes selling units) that costs 1000 resources, which would take you 5m to get up to. Especially if when sai

What if you suddenly unlock a unit (or maybe a shop comes selling units) that costs 1000 resources, which would take you 5m to get up to. Especially if when said unit becomes available isn't predictable, it may be a huge advantage to have some resources in reserve. Furthermore, if you're already at the unit cap, and all your building are already working at peak efficiency, there may be no good way of spending those resources without wasting them.