It's not that hard to warn someone a few days in advance

I've been a dm now for 5 months and I've run a couple good campaigns but this last one has utterly pissed me off 4/5 are brand new and want to build a character and start playing but never show up to a game to either guy is awesome and a good friend of mine so at least he lets me know a few days in advance, but the other people I swear to god let me know two hours before start that they can't make it when I have asked them multiple time to warn me at least 24 hours in advance. So I have spent the last month and a week hanging out with my friend waiting on people who said they were going to show up only to find out last minute that they aren't coming. TLDR: if you are planning to do something with a large group of people let the person know ahead of time if anything comes up or if you really don't want to do it cause stringing that person along for a month and never showing up just wastes his time.