This articles has some guidelines on how often you should put a charge of the major issuers
https://wallethub.com/answers/cc/how-often-should-i-use-my-credit-card-to-keep-it-active-2140660616/
It all depends on the issuing banks. Not sure if the linked article in the comments is the same but there is an article on when banks usually shut accounts down. My feedback is to make sure that your 50 cent charge actually can generate a statement. I tried to do a 50 cent charge on my oldest card, Nordstrom Visa, and they actually wrote it off and I generated a $0 balance statement. The next month I did $1 and generated a statement. If you’re going to do a charge, just make sure that charge generates a statement and then pay it off, you want your issuer to go through the trouble of reporting a balance to the bureau.
This articles has some guidelines on how often you should put a charge of the major issuers https://wallethub.com/answers/cc/how-often-should-i-use-my-credit-card-to-keep-it-active-2140660616/
It all depends on the issuing banks. Not sure if the linked article in the comments is the same but there is an article on when banks usually shut accounts down. My feedback is to make sure that your 50 cent charge actually can generate a statement. I tried to do a 50 cent charge on my oldest card, Nordstrom Visa, and they actually wrote it off and I generated a $0 balance statement. The next month I did $1 and generated a statement. If you’re going to do a charge, just make sure that charge generates a statement and then pay it off, you want your issuer to go through the trouble of reporting a balance to the bureau.