I clean mine sparingly, as I find the more lube/oil you add the more grit and crap sticks to it… making it dirtier quicker and more likely to stiffen up (or bind as I think it’s called).
As said before, if riding through poor weather every day then cleaning intervals may be once a week. But over the summer months, I clean it once a month with chain cleaner and a light spray of lube. The ‘X’ rings (or ‘O’ depending on the choice) retain a lot of the required lube, so adding loads of lube isn’t really required unless you like spraying your rear end in sticky residue.
I will mention though I’m mainly road riding in good weather. If you venture off road a lot then the chain will need cleaning probably daily. So it depends on your riding, when and where and frequency… that is an obvious and pointless statement I realise so apologies.
Other thing to note, you could just budget on a new chain every 20k and just ignore cleaning, as the cost of a chain isn’t much when you think that mileage might be a few years riding for some.