When it comes to friendship, I have two principles: 1) just like any other relationships, friendships need work from both sides and 2) people change, so some friendships have an ‘expiry’ date.
If I have to sum it up, I believe that my best friend is one that makes me his/her priority, and not just an option.
If I have to know about important events that are happening in your life (e.g. new relationships, engagements, weddings, pregnancies, breakups, etc) from someone else along the 6-degrees-of-separation, I know I am not your priority.
If you always respond to my invites for hanging out (or any other invitation for that matter) with “I’ll try to make it, but I can’t promise you” or “Yeah, sure, let’s arrange something one of these days” or something similar to those phrases, I know I am not your priority.
If you only call me once in a blue moon and after an acceptable amount of (fake) pleasantries you start spewing stuff about yourself and yourself only, I know I am not your priority.
Friendship is two-sided, and I am not sorry to say that if I am the only side that is doing all the work to make it happen, then you are not my priority anymore.