this is especially true for siege engines. If they become mostly maintenance, it will be difficult to carry them around when there is no siege planned; while it will still be difficult to buy them at the last minute. This could unbalance siege warfare.
that was already like that. going around with enough siege engines to be effective in a siege was a pain, it really made an army less effective. It's indeed a different kind of "it will be difficult to carry them around when there is no siege" but it's still an already present effect.
