@Stephanie_A that is, unless you build your printer from PLA. Bwa hahaha. 
@Rob_Wilson I agree. I bought 2 pieces of 2.5mm window glass for $2 each more than two years ago - I haven’t ever unwrapped the second piece. I print using PLA, ABS, and PETG on glass with hair spray. Also, because of the light weight, I’ve never had problems with layer shifts and I print as fast as 100mm/sec.
@ThantiK been there, nothing is more nerve wracking than printing replacement parts while your printer is held together with superglue and duct tape. But even then it stayed in calibration enough for me to fix it.
@Stephanie_A I only mention it because I’ve done the same damn thing…rofl
Nope, you are not alone. I level my bed about every 6 months
I have to disagree on that especially in case of delta mechanism.
Yes manual calibration is doable and yes I can do that.(It’s time consuming for sure)
Auto calibration/trimming/tramming or whatever really save me a lot of time when I’m trying to upgrade some part that might have different dimension from original parts.
Or maybe you have quick change nozzle/print surface or something along those line auto level is really helpful, just drop it in and run auto level and you are ready to print.
To me everyone that have 3D printers should know and practice how to do manual calibration just in case auto level is not work for some reason, other than that I just don’t bother and run auto level. 
@Mark_Rehorst You must think I’m stupid, you are underestimating me. My temp gun is not lying, I was measuring with nicely scuffed kapton tape well coated with ABS slurry, the surface was not reflective in any way, shape or form, far from it. The temps I was getting were well within range of the readings the thermistor were giving.
I have plenty of time, I’m a pensioner, though I doubt anyone would’ve been much quicker in bringing a new printer online, auto tramming or not. Sure I spent a little time playing with temps, feedrates etc, but that was to get used to the materials which were new to me. I use google well though, and that was well under control rather rapidly.
It was Arduino that got me into 3D printing, not the other way around, I was playing with motor control and came across 3D printer projects, being an old CNC guy I thought how cool it’d be to have a CNC sitting on my coffee table, not to mention all the mechanisms and parts I could produce bespoke for almost any project that popped into my head. So updating Arduino and c++ code is an absolute doddle, nothing complicated about that in the least.
After half a lifetime of setting up machines to an accuracy orders of magnitude greater than any FDM printer will ever need, I found the whole experience a walk in the park to be honest. In fact there was very little challenge to the whole exercise, I wish there were more, I like to tax my grey matter solving problems, that’s where my satisfaction lies these days.
Manual mesh leveling ftw
Coko
@Gary_Craig Hihi If I had an unreliable printsurface, that needed meshleveling and thus distorting the whole print, I would just exchange the printbed to a flat one Meshleveling and ABL are just covering the problem. Get yourself a casted alu plate and be happy for the next years…
Shhhhhh
@Rene_Jurack I hear you, but I have 3 cartesian printers, one came with an aluminum build plate 12x16, the others were 10x10. The variance in level is as much as .3 at any given point. I replaced the aluminum with glass and using mesh I can lay a .1 mm single layer across the entire 10x12 builid surface without problem. My prints look great, I don’t see the need to spend money on a machined aluminum plate. Yes, I would prefer a perfectly flat build plate… but why spend the $. Even my Rostock V2 now uses a form a mesh to increase accuracy. You can’t argue with results. And no need for a probe also. I am good with the solution.