are there days where you only train certain parts of your body / only do certain exercises because you simply don’t have the time for a full workout?
my ideal workout means stair climbing, running-walking and stretching. It can well last 2 hours.
Some days I don’t have enough time to do all that. Would it be better to do less of each kind of exercising or just to fixate on one kind?
I switched to working out at home and saved a whole bunch of time I used to spend getting to and from the gym, plus all the faffing about waiting to get on the stations I wanted to use. Its not going to work for everyone but if you can do some sort of workout at home or at work if you lucky enough to work somewhere that has facilitates, then you can save a whole bunch of time.
As others have mentioned switching to high intensity can give you as big an impact in a lot less time. Unless you training for endurance events spending a couple of hours working out everyday can actually be counter productive. I used to train twice a day six days a week, an hours weights in the morning then two to three hours of BJJ/Kickboxing and I never made the same strength gains as when I toned that shit down.
Two hours is pretty excessive, you should be doing 10 minutes stretching tops, unless its an actual stretching workout such as yoga or you are working out an injury. Spending an hour on a stair master or a runner is only good if you actually challenging your heart rate during that time, and then only if you working on endurance for a reason.