to maintain level 5 military is extremely easy. roaming the belts for 2 hours (with one guy) will get you like 20 % of level 4 to 5 if that is any indicator. if you are running the noob anomalies it goes ALOT faster. if you have a dedicated team of 3 + people running the belts, and any anoms that pop up, i can almost assure you that you could go from level 1 to 4 in a single day, and probably level 5 the next day. to maintain it just takes a few sanctums/havens run a day, which i can guarantee you they will lol.
the industry index on the other hand takes ASSLOADS of ore mined to keep active. and the only belt that is worth mining completely is the large belt. the small, medium, x-large, and giant belts are only worth cherry picking and letting them re-spawn naturally every 3 days. the reason you mine the large belt is it is economical to completely mine it out, because as soon as it is mined out, it will re spawn within 5 minutes giving you all the ABCs and everything else in it again.
honestly you need like 5 people mining all day to maintain level 4 (few more for 5) and that may not sound like much..... but i do mean literally all day. the only way to see how fucked up it is to keep industry level 5 is to try and get it yourself lol. the amount of people it takes to keep level 5 would almost guarantee that no on would get a decent amount of ABCs because there is just not enough to go around with that many people. also level 5 industry is a BIG beacon for pirates and such to come and try to get some easy kills, you are better off with multiple level 3 industry systems.