choose one or more of the traditional starting ones: Mort, Small Gods, Guards! Guards!. If you read all three of those and like it, just go back to Colour of Magic and read in publication order. The world evolves as he writes and it’s a better experience.

This here. This is what I recommend to everyone I introduce to Discworld.

I haven't kept count of how many readthroughs I've done, but every few years I do one too. I had my copy of Guards Guards rebound recently because it was literally falling to pieces.