Traditionally I have run mostly homebrew adventures. I've used encounters taken from commercial adventures every once in a while. The Dragonlance campaign I'm running is the first I've really tried to run a module straight.
My players aren't always going along with that idea but that's ok. I've also added some content because I wanted a special event for the character with divine powers. I plan to do the same for the knight. Due to this I created Dulsi's Dragonlance Addendum on DMs Guild.
For Spelljammer I found the process less satisfying. I had to tweak many individual encounters to match what I wanted. So running it requires looking at the adventure and looking my notes for things to override.
In the past I’ve always run entirely homebrew adventures and settings, but I recently started Waterdeep: Dragon Heist to save some prep time. The campaign is okay overall; it’s great to have an existing setting with decades of existing content if needed. I’ve found myself having to redo or add a lot though: the campaign was obviously designed to be run for 4-6 players, so with my smaller party of 3 I need to come up with more encounters and rebalance what is there. I also can’t stand some of the tropes they use and re-fluff them to be more dynamic.
I don’t think I’ll do a published adventure again. I’m open to existing settings now, but the style of published adventures just doesn’t vibe with me.
I just ran a Dragon Heist campaign, but I used the Alexandrian remix of it because it seemed interesting. Even then, I added some stuff I thought it needed and removed some stuff my players wouldn't have been interested in. The ghost in Trollskull was nothing but a piece of set-dressing, as I knew they didn't want to make a tavern.