The most common first-layer problem has almost nothing to do with the printer and everything to do with three basic steps, done in order, that are easy to skip when a print is already running late.
- Clean the bed with isopropyl alcohol, every time — fingerprints and dust from handling the plate are enough on their own to cause a corner to lift
- Re-level after any bed temperature change — the plate expands measurably between cold and heated, enough to throw off a level that was correct when checked cold
- Slow the first layer down, even if the rest of the print is fast — the extra time spent on layer one buys far more reliability than it costs in overall print time
Skipping step one is responsible for most of the failed prints I see people asking about, and it's the easiest of the three to get complacent about once a few prints in a row have worked without it.
Step two catches people out specifically because it seems unnecessary — the bed was levelled, why would it need doing again? But the physical expansion of the plate at temperature is real and measurable, and a level that was correct cold can be off by enough to matter once the bed's actually up to printing temperature.
None of these fixes cost anything beyond a couple of extra minutes before hitting print, which is a small price for not discovering a failed corner an hour into an otherwise good print.