There's been two major disruptions in my experience.

First was Lidarr went for months last year (was it this year?) unable to search/add musicians due to complications with how they were relaying those searches. It took them a long time to refactor that part of the software and make it usable again.

Second was the retirement of Readarr, the ebook-version of this software, which was an absolute shame.

But aside from that this is pretty much set-and-forget software. Although the setting is harder than it should be, should be much easier to favour smallest x265 rips at <resolution>, lossless audio, season rips with subtitles.