Are professional painters worthwhile? Or do it yourself?

Everyone has to decide for themselves what something like that is worth to them.

That's what I'm trying to find out, because you don't know beforehand how much "better" it would become.
Painting white paint on the wall sounds at first glance like 90% hard work and 10% experience.
But maybe it's more like 30% hard work, 10% skill, and 60% experience that lead to a good result?
I have also done it myself several times in rental apartments (with results satisfactory to me). However, always on textured wallpaper.

I buy expensive paint, reasonable brushes, and do it with [Kumpel]

You can do it yourself, it won’t be worse than an average painting company if you put in the effort.

Financially, everyone has to calculate for themselves. It’s really not worthwhile. You have to buy paint more expensively, painting companies have equity. Then you have to calculate your hours (a layman needs at least 3 times as long) and also materials like brushes, masking tape, scaffolding, etc.

We calculated it back then, with my hourly wage we might have saved about 2000 euros for inside and outside.

Honestly, I’d rather sit in the warm office.

Scootering requires a bit of arm stamina for a house like this with ceilings, etc.

We did the basement ourselves. It started with little "things" like the corners never quite turning out right. How often I accidentally dragged small scratches with the metal edge of the roller that barely protruded...

But what was especially annoying was when you spread the grains from the plaster on the smooth ceiling. What I wouldn't have thought I was capable of: filling and sanding the joints...

I’m still glad to have had the painter for the ground floor and the upper floor. They were sometimes two of them working for a week (spraying textured ceilings), and it wouldn’t have been worth my time to do it myself (but we did manage to do quite a few other things ourselves).

My parents built a house in the early 50s, and from stories I know that wallpapering and painting were all done by themselves even back then. Or to put it another way, the house has never been entered by a painter. And I don’t think our painting and wallpapering work is that bad.

So I do think you can manage it yourself so that it can keep up with the work of a professional.

By the way, except in the basement, I would never paint plaster directly but always put paper in between. It’s certainly easier if you ever want to remove the paint completely.

And taping off door frames, etc., is not rocket science either. Just now there was cheap crepe tape at a big discount store; maybe you can still find it in one or another branch.

If you want to paint yourself, then first work on the corners with a wide brush and only then use the roller, making sure not to get too close to the other wall with it, especially if that one is already painted.