I did mobile deposits with my Merrill Lynch account last year, until I got closed down. That's the only time. I keep a log of my MO numbers.

My worst MO incident was where 8 of them got lost in the mail. And I was awkwardly placed to make too much fuss with the bank because my father worked for the bank doing, among other things, delivering the mail. They found them 4 months later in a supply cabinet. I guess someone had them in their hand and put them down to get a box of paper clips and they sat there for a while. I had to pay the then-$15 fee to get them replaced. Oh well. Cost of doing business.

I have about 12 banks/CU's that I use, and I do mail deposits. I've noticed that they get posted more quickly since the virus - I assume they make a point of checking the mail every day.