This is what I think you're trying to ask: When I have a DHCP network but want a handful of hosts to have static IPs, is it best to reserve the IPs on my DHCP server or set static IPs on the hosts themselves? If that's your question, edit it and I'll take out this paragraph.
The only benefit I see of configuring static IPs on select hosts themselves is that the address is permanently set and not relying on the interface's MAC to reacquire the "reserved" IP. However, reserving the address already handed out by DHCP is quick and easy and doesn't require any access to the host. For instance, if I put a wireless print server on my WLAN and want it to maintain a specific address but don't care what, I can reserve the address it is assigned without ever touching the print server.
As an aside, you mention this is a small business. For an office of five or 10 people I would personally set static IPs as a best practice. No DHCP server needed, nothing ever changes, and perhaps it adds just a tiny extra bit of security in that one can't just plug a device into the network and have instant access.