What should an office self host?

Any form of documentation (processes, design decisions, …) might be better off in some form of wiki than in a loose bunch of .doc(x) o .pdf files.

I work for a crowd that only does foss or what ever we can build ourselves

PABX is done locally File servers of course, Asset management and tracking built in house Time and attendance built in house Generator management Mail server for outbound mails Projects board Several internal websites

Put LibreOffice on all the desktops and GnuCash is a great highly customizable accounting program.

Your business should focus on what makes it special. Printers don't make banks special so they should NOT make their own printers.

Anything except what makes your business special is a DISTRACTION, that especially means software. Buy anything that is even remotely like a printer.

Conversely if there is something that makes your business special, YOU must do it yourself. If that means self hosting some open source thing it ALSO means you need to become maintainers of that open source thing.

Own the things you need to be good at outsource EVERYTHING ELSE, no exceptions.

Here's a really gray example to drive this home

Let's say there's some part of your business that needs to print invoices on paper that's as thick as blue jeans. You look and look and look and no one sells printers that print on that kind of paper. You have two options, 1. Realize that it's probably dumb that you are trying to print on paper that thick and change your business to deal with regular paper, or 2. Decide that that's what makes your business special and start manufacturing printers.

i use Nextcloud for file storage and project management, it's been solid for time reporting and client acquisition too. might be worth checking out for your office!

Ask your IT-Guy. If you don't have one, you shouldn't selfhost at all as a company.

Whatever you do, make sure your backups are solid. Consider it while you make decisions on what software, and services to use. "I'm going to set up nextcloud today, how am I going to back that shit up?"