If you or your SO work a typical 9-5 salaried position, how much overtime do you typically put in and when and how is that arranged? Do you often know well in advance or is it usually last minute? If it's last minute, how do you plan your life outside of work?

I am getting really frustrated with DH's company and how they deal with asking for extra work time so I am curious if I am being unreasonable and this is the norm or if they are asking too much from their employees. I SAH now but in my previous jobs I did put in a lot of overtime but I always knew when to expect it. Sometimes there would be random late nights but usually I had a pretty good idea when I would be busy and need to put in longer hours or work over the weekend. In my field it was always an issue of extra workload at certain times, not that work had to be done at specific times.
For DH, he is working on a project that sometimes requires him to work off hours, late at night or over the weekend. I 100% understand that but often they will not express any need for work outside normal business hours until they ask him to work all weekend on Friday night. (And they have weekly 6pm meetings on Fridays too, who does that!?!?) They do this at least once a month and we never know when. This is in addition to the weekend work that typically happens once every 4-6 weeks which is actually planned in advance. I am getting so annoyed because today he sprung it on me that he may have to work over the weekend and we have had plans to go away next weekend for months and now they want him to work then too. I feel like we can't have a family life outside his job and it's driving me crazy. He really only worked one other professional job before this and the overtime work was known and planned out well in advance, similar to my previous jobs, so that is what seems "normal" to us.

So what is typical? Do I need to just suck it up and deal?