my real concern is how long they last - i only have access to equipment every so often - read into that what you will. So, if they last 5 years, then it's time for a new one. If they last 10, then I'm good.The only real advantage would be to have a spare for troubleshooting or replacement in case of failure. If it's free or really cheap it might be worth it, otherwise, no. I believe ShawD covers dish and LNB repairs or has that changed?
Note: The 60e and 75e LNBs are not interchangeable.