I don't think they need cleaned after a month. Or lubed. I base this on nearly a decade of owning, shooting, and daily carrying Glocks, as well as talking to a great number of other people who have done the same.
It is owner dependent. In September we lost power for a week. For 172 straight hours it was running generators for well pumps, sump pumps, the house, shop, chainsaws for a month cleaning up downed trees, damaged trees, then shredding and distributing free mulch. On top of regular farm activities like bailing hay and so on. My Glock was so full of saw dust it should have been cleaned a few times a day. Waiting a week would have been a bad thing.
These things are like a huge F150, lifted and best tune, fattest stupid tires, after market parts, then used as a milk and bread fetcher. Or the same truck used as a farm truck. Same tool, different uses, create different maintenace needs.
Fetching milk and bread I could get away with a yearly cleaning even with the 3,000 rounds I shoot every year from it. I can't go more than a week most the time and it's pretty dirty when it does get cleaned. One thing I do like, no matter how dirty my Glock gets, it always goes bang and always feeds the next round.