Quesion after rooting

[Guest phillevy]

I have successfully rooted (using adb, clockworkmod recovery etc) and all seems fine. What is puzzling me though is that I don't lose my custom recovery when I reboot - all the guides talk about having to rename the install-recovery system file to stop the original recovery flashing each reboot, but there is no such file on my system and I've rebooted many times now without any loss of clockworkmod.

Aside from not knowing how to restore my original recovery image, can anyone explain what is going on and is this ok?