How To Convert Your Old T8 and T12 Fluorescent Fixtures to Brighter LED Bulbs

Here are the LED bulbs I'm using: https://amzn.to/35544X3

New LED bulbs are greatly superior to the old fluorescent bulbs. They draw far less current per lumen, so you can put a much brighter bulb into the same old fixture. But ... you (generally) need to modify the fixture first!