All businesses need servers! Even a one-man-band with a laptop needs one.
Any desktop system by virtue of the fact that there is a human using it, will eventually crash & burn. The trick is to ensure that you have the data backed up and the best way to do this in a business is to set up a server.
1) It keeps user data off their workstation
2) Data can be easily shared with colleagues
3) It is easier to arrange backups (the system is running 24*7)
4) It is a legitimate business expence
And I have only talked about the data. What about other shared resources (Printers, email, Internet, etc)? They all benefit from being centrally located. Hanging a printer and some file shares off Mary's PC might be simple to set-up but if the PC is turned off, what good is it to you. What happens if Mary accidentally deletes some files? What happens when 5 more people are trying to access the same data?
It's been proven time and time again, companies that loose (financial) data go out of business.
The actual server OS (Windows, Linux, Mac, etc) that is set-up is irrelevant providing it can do the jobs that it needs to do.
If you are called in to set-up a small office network, you need to sit down and let the client tell YOU what they need, then you put together the package that will do the necessary jobs for them within the budget specified.
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