There are also legal limits on working time, although it's not clear to me which would apply to a warehouse worker.

https://www.eurofound.europa.eu/observatories/emcc/erm/legis...

Take a look at "Work involving continuity of operation" part. Amazon warehouses have 4x10h system AFAIK.

You can legally opt out of the working time limits in most professions, except for limited few like truck drivers. I'm yet to see an employment contract that doesn't have a clause for the opt out. I work as a programmer contracted for 37.5h/week but of course there's a clause in my contract to say I agree to work more "if needed"(never had to in my 7 years of work here, but still).

Overtime on UoP is permitted, but regulated. You can't do over some limit (like 400 hours yearly); except if you're a doctor.

Interesting. Here it's company to company, you can have benefits part time, but most don't offer it as most part time jobs are low wage. (Less likely to have bennies)

Also, "benefits" mean very little at that level in Poland, since healthcare is state run - and shit, but equally shit. Private healthcare is usually diagnostics only (also, dentistry and some "luxury" operations like LASIK).