Changing one default setting fixed EVERYTHING

[frobot 0]

I have been 3D printing daily for the past 3 months (Ender 3 pro) and it has been a nightmare. Getting the first layer right was near impossible. Getting a successful print was a process of very meticulously leveling the bed, trying to print, stopping it to scrape off the failed layer, releveling and repeating until I get the lucky run where it somehow sticks. I tried 3 different bed surfaces (original, glass, and another magnetic one), 4 different filaments, all ranges of temperatures, a new nozzle, changing nearly every slicer setting, and every possible bed height with no change at all. 
Finally I changed the first layer height to 0.25 and the first layer width to 120% (width of 0.48 after first layer) and not only does it print perfect every single time, I can't get it to mess up. I went back and tried all the different beds, settings, nozzles, filaments, etc. and I can't find a combination that doesn't print flawlessly.
The default layer is just way too thin to adhere. And changing your layer height doesn't change your first layer height which I didn't realize. Hopefully this helps someone. And hopefully if others have the same problem we can get the default changed and save some people from what I went through. 

[geert_2 560]

Indeed, the first layer is crucial. For me, 0.1mm is too thin and gives occasional blank areas (=uncovered), 0.3mm is too thick and reduces bonding, and 0.2mm is best: this gives good coverage and good bonding (glass bed). But for other materials, beds, and printers, it could be different.

 

Normally the bottom looks like this (ruler is in mm and cm):

 

For PLA and printing on glass, wiping the glass with a tissue moistened with salt water greatly improves bonding, compared to printing on bare glass. See my old manual here (and then scroll down a bit):

https://www.uantwerpen.be/nl/personeel/geert-keteleer/manuals/

 

For me this works very well on long flat models like rulers and calipers. Not very suitable for narrow high models like poles: they tend to get knocked off. So, stay with the printer until you know by experience how well it works for you.