Flaky friends (not talking about dandruff!)

⚪Hula👶👶👶 • left glow for a break. I may come back as some point but for now its taking too much of my time
How many chances do you give friends that are flaky? These are people I love and spend lots of time with. Its just that they are so into spontaneous things that those are usually when we do stuff. Should I just forget about including them in my plans when I'm organizing stuff? Occasionally they will come after not letting me know they can make it. But then more often than not, they will cancel last minute. I assume they don't have that many last minute emergencies. Its more probably a wait and see what the more fun thing to do is. It definitely makes me love my reliable friends even more. But when do you quit including them? Or do you just invite them and assume they won't come? I've been going more for the second one but it still pisses me off