Is it good to have multiple version of Linux Kernel?

Once, I was installing some kernel patches & something went wrong in live server where we had 100s of clients. Only one kernel was there in the system. So, The server was down for sometime and using live cd, we made the system up & running & did the further repairing work.

Now my question, Is it a good idea to have a 2 version of Kernel, If kernel is corrupted we can always reboot with other available kernel ? Please let me know.

Also, Is it possible to have a 2 version of the same kernel ? So that, I can choose the another kernel, when there is a kernel corruption?