Is your cupboard (or other) door scraping against the frame? All you need to fix it is a power plane (the type with a blade, not wings).
You can use a regular manual plane, but why would you? Power tools are fun.
The Problem - Rubbing Door
Here is a photo of my linen cupboard. I’ve circled the problem. The left hand door is scraping the other door. No amount of hinge adjustment or other messing around is going to fix this, we have to modify the door.
How to Fix it
Step 1. Mark out the door
Grab a ruler and draw a line, marking the amount of wood you want to remove. Note that if it is a hollow core door, there is a limit to how much you can remove. A few millimeters is going to be fine, but don’t start taking huge chunks out. The door pictured is a hollow core door.
I’m removing about 1mm, to keep the gap between the doors as uniform as possible.
Step 2. Remove Door
How to do this will vary depending on the type of hinge you have, but it is generally a matter of undoing the hinge screws, while not dropping the door on yourself.
If you are going to drop a door on yourself, try to ensure it is a hollow core door - they weigh far less than a solid core door.
Step 3. Plane the door
Lay the door down so that the face you are planing is flat and easy to run the plane over. Ensure your power plane is set to take off a small amount of material (I went with a 0.2mm setting). This is to reduce the chance of damaging your door.
When you do plane the door, the direction should be from the outside in. When you lift the plane (after shaving some timber off), you should still to be on the door.
Keep planing until you reach the line you made in step 1.
If you run the plane the other way (off the end of the door), you greatly increase the chance of taking chunks out. This means your door will either be destroyed - or just look crap. You would need to use filler to fix it.
Step 4. Admire your handywork, rehang door
Have a look at your door. Ensure you have taken off the right amount of material. I found that I needed to give the newly planed surface a quick sand with some 150 grit sandpaper to smooth it over a little (I probably need to sharpen my plane more often).
Once you are satisfied, refit the door. Check that it now opens correctly. If not, take it down and go plane some more.
Update: @MaximRouiller informed me that I did not have a picture of the rehung door. Here it is…
Step 5. Paint
The final thing to do is repaint the planed edge of the door. Doors are usually painted with a high gloss enamel. If you want to match the paint, get a piece of paint that your plane has taken off, and have it matched at your local paint / hardware store.
Now you know how to fix a scraping door.