I had some robust fluorescent light fixtures that were hardwired and I did not want to replace the housing. I went with replacement bulbs. I had to remove the ballast before installing the new LED. Pretty easy to do. My bulbs came with replacement tombstone sockets. It was a while ago, but I believe I was able to use the tombstone sockets that were already in my housing. The replacements significantly increased the light in the shop and the removal of the ballasts got rid of that annoying hum.

This is what I used.