I've definitely left ping running for hundreds or thousands of pings. That's partly how my roommate eventually diagnosed this weird issue where our wifi would drop packets (or have really highly increased latency) on a suspiciously regular cadence. You could easily see the pattern in the pings once the tool ran for a while. It turned out to be a firmware issue with our router, but we would not have thought too look at that if we hadn't seen the pattern of connection issues.