My requirements were: - ability to sync the TODO lists between devices (web and android). - ability to have sub-items, so that I can organise my complex lists into magnificent trees of tasks. I sometimes have 5 levels of details on some travel checklists. - ability to handle periodic tasks, and ability to create a task and hide it until a specific date (topics for my future self) - ability to be self-hosted.

I'm now using Vikunja, and Tasks.org for the Android side. That setup has worked for me wonderfully for a couple years now. Vikunja has a ton of features I don't use, and that's fine. They don't get in the way.