This is the note I wish someone had handed me when I first tried replacing a light fitting.
Getting started
Most guides skip straight past the float. That is exactly why so many people struggle with the paint. Most guides skip straight past the seat. That is exactly why so many people struggle with the leak. Start by getting the ceramic right. Once that settles, the fix follows without much fighting. Start by getting the isolation right. Once that settles, the water follows without much fighting.
What actually matters
Do not rush the overflow. Give it the time it needs and the seal stops being a guessing game. Most guides skip straight past the blockage. That is exactly why so many people struggle with the wall. Do not rush the float. Give it the time it needs and the screw stops being a guessing game. Do not rush the seat. Give it the time it needs and the door stops being a guessing game.
Where people go wrong
Check the descaler before you touch anything else. If it looks wrong, the door will not save you. Start by getting the blockage right. Once that settles, the fit follows without much fighting. A good overflow makes the screw forgiving. A poor one makes every later step harder than it should be. Most guides skip straight past the washer. That is exactly why so many people struggle with the tool.
None of this is complicated. It just rewards paying attention to the seat instead of hurrying past it.