I hate when friends take for ever to let me know if they can hang over the weekend and in some cases just text back. Since sometimes they say no and it ends up being late to make new plans with someone else.

Sounds like they might be waiting for a better offer.

Live and learn who you can count on and who isn't that interested.

That sounds like a very reactive way to live...... perhaps you should investigate making your own plans then just seeing who comes along for the ride?