Getting reliable results
It's always frustrating, when a print is going wrong. Sometimes results are salvageable (more on that later), often they are not. What's even more annoying is, when prints fail inconsistently, because then printing anything becomes a risky gamble.
That's why it's important to achieve a setup where good results are predictable and the risk in printing more complicated parts becomes calculatable.
One of my biggest struggles is flaky build plate adehsion, in other words: my model sometimes wont stick to the build plate. Smaller models will fall off in the printing process (predictable), bigger models develop dog-ears (ok), or my printer just creates a shrub of filament (bad).
It's known, that some build plates for Ender 3 come slightly warped and that you just have to find regions where printing is possible. FYI in my case it's in the middle back and it sucks because you can't print anything bigger than ten centimeters in diameter.
I noticed something. After an initial print, second attempts come in more reliable. I've started preheating the build plate at 80°C for 10 minutes, letting it fall down to 60°C when starting to print. Suddenly I am able to print huge, flat objects, like walls, without having them rolling up in the first hour of printing. Great.
Now I have to find out why my printer sometimes decides to suddenly continue printing at an entirely different spot than instructed, and I am all happy.