I just don't understand in a group of people who enjoy playing why is it so hard to just have a day or two a week set aside to play.
You answered your own question. It's because...
everyone has a life outside d&d, we all have jobs, families, and other hobbies/interests
The problem is that four five people to get together for a game, you have to find an intersection of five different schedules. If you knock out all the times player A is busy (work, family, other hobbies), then the same for players B, C, D and E, it's not going to be long before there's no time left at all.
Essentially, someone (probably everyone) is going to have to be flexible... or accept that they'll have to drop out of the game.
in our group of five people we have four different campaigns going on(we have different campaigns for different combinations of people cause we don't want anyone getting to far behind in our main campaign)
So does anyone have any suggestions, have similar problems, or just want to complain, please do.
Firstly, drop four of the five campaigns, leaving only the main campaign going. With too many games going, it's difficult for people to maintain any sort of a focus, you never make any progress, and so it's no wonder people are getting frustrated and losing interest.
Secondly, set up a fixed and regular game night, and then
never cancel it (or as close to never as you can reasonably manage - in the worst case, keep the game night on, but spend the time playing a board game, watching a film, or something else instead). By having a regular time, people can make their plans in advance, and so will find it easier to arrange to attend.
Third, don't penalise people for missing the occasional session. Accept that people will be there if they can, and so if they aren't there then it is for a good reason. Have the character drop into the background, but otherwise carry on as normal.
If someone is routinely not there, or consistently drops out at the last minute, then consider dropping that person from the group. Assuming they agreed to the regular game night, then a consistent failure to attend means they're just not interested, but didn't want to tell you so as to not hurt your feelings. Consistently cancelling at the last minute is just rude - yes, we all have emergencies to deal with from time to time, but we don't have emergencies on a weekly basis.
(Is there a reason why the late-canceller does so? Does he have kids that he might have to look after at short notice? Does his significant other secretly not approve of him gaming? Or is he just useless at making plans and sticking to them?)
And also just out of wonder how often do you guys play and how long do your sessions usually last?
I have two groups.
The larger of the two meet on weeknights on a bi-weekly basis (although we have a couple of campaigns going, so people can play every week if they prefer). Sessions typically last between 2.5 and 4 hours.
The smaller group attempts to meet on a Saturday on a weekly basis, for six hours at a stretch. However, the numbers in that group have fallen to the point where if any of us cancel then the game is off... and one of us has to cancel most week. Since our glorious restart at the start of September we have managed to actually get together a grand total of... once.