For shared and reseller hosting is still fine. The main issue here is for dedicated server client. You have to pay your license and rack fee in advance, before your client pay you.
If you are reslling dedicated server it is worst. You have to pay the server rental fee to your datacenter, but your client ignoring your email.
Looking for a flexible datacenter is important here. Make sure you do not signup a long period server in return to get more discount. When your client cancel your server without notice, you have to pay for the rest of the rental or else all your server with the datacenter will be suspended.
