Some cameras have 2 card slots with the same type of card in each.
I download a card to my computer, verify it is downloaded and do the following:
take the second card out move it from slot 2 to slot 1.
Take the former slot 1 card and put into slot 2.
Then reformat both cards.
This way each slot is being used equally.
Works for me and who knows if necessary but that is what I wanted to do.
Do others do something different?
I know that those with 2 different types of cards cannot do this so they do not need to comment.

First, Sony and Canon make wonderful cameras, but I'm not going to switch systems and I really do love my Nikons so please refrain from posting about other systems. I have 3 Nikon DSLR bodies. I have no objection to mirrorless except that because everyone wants them, DSLRs are at fire sale prices. I have a D600, D750 and D850. I only recently bought the D850 and as far as I can tell it's a better camera than everything that came before the Z9. And what an amazing workhorse my D750 has been! But it finally started to succumb to all the abuse from dozens of weddings, travel, and on and on. The hotshoe stopped functioning and that's vital to my professional work so sent it off to be repaired asking for an estimate to repair/replace the hotshoe and generally go over the camera and see what else needs to be done. The shop came back with a cost of repairs that pretty much need to be done, at over $500. OK. That's a lot for a 10 year old camera with 120,000 clicks on the shutter. So thinking of trading it in as is, along with the D600. But what to buy? I'm not interested in going to the Z line because I have to either do everything with an adapter or buy new Z lenses. If price were no obstacle then a Z8 would be the way to go. But price is an obstacle. $4 grand for the body only, plus the adapter or Z lenses - just can't justify the expense. So the question is should I buy a used D750 or a used D850? I prefer to shoot the D850 at 25 mp resolution so forget the resolution diff. The D750 is a lot less money and weighs a little less. But the D850 has a much better AF system and handles much higher ISO levels. Low light performance is important for weddings and my hobby is shooting at night - the milky way, light painting, etc. So handling noise is important but so is low light focus ability. I've always had a lot of trouble focusing the D750 in low light because once you lose any contrast, it can't do it. I only just got my D850 so not enough experience to know. For you D850 owners, how good is it at getting focus at night? Anyone have both a D750 and D850 that can weigh in?