Health and Safety at Work
So your better half has decided that they want the sockets in the Lounge changed from Plastic to Chrome Plated. What do you do ? Put on your rubber boots and gloves and start to work being really careful not to touch an exposed wire! or do you switch the circuit off then perform the upgrade ensuring everything is correct. I know my preferred method!
Danger is my middle name
Now in networking terms being a Cisco CCIE I often have to put on my rubber boots and gloves because working on any configuration on a Cisco IOS Router (except new ASR9K) that is effectively what you are doing. One wrong command and you are gonna get a shock!
Need to read more
I never really gave this much consideration, I just accepted it as the way it is. Now I see this as complacency on my part. Anyway my competency was challenged when I started to read into Juniper JUNOS. (Don't worry if any one seen Juniper it on my computer screen at work, I just flipped over to YouTube).
Cisco please copy
When you work with JUNOS you do not work with the live configuration, you work with a work in progress (Candidate) configuration. That is not the best bit, the best bit is that you can issue a "commit confirm" which means you commit the configuration and you have a period of time before you have to enter the "commit" command again or else the configuration will be rolled back to the previous configuration.
How many time have you locked yourself out with a dogey ACL update, or IPSEC went pear shape, this is a command I now dream of having in IOS. It is so much more elegant than "reload in". Please Please Please Cisco get this feature in IOS.
Cisco IOS Today
So Cisco do have some Roll Back Features http://stack.nil.com/ipcorner/ConfigReplacement#chapter4 however it not very elegant IMO. And you are relying on having a full config pre-prepared, instead of preparing it on the actual end device.
Service Providers you lucky beggars
Note : ASR9K and IOS XR 3.72 has "Commit confirmed" which appear very simmilar, but I do not expect to see many ASR9Ks in Enterprises environment any time soon.