Barely done this for a month now so the process is still young, but my plan is to keep around only the relevant snippets and update them in case anything changes. As to how often I review them, or the backlog, basically whenever I have time or I feel like doing it (trying not to put more pressure on me schedule than necessary).

The only things that I do "urgently" would be to add elements to the backlog, and to fix errors in the published snippets. For everything else, I put a reminder in my calendar for the weekend, or after work in case I feel energetic enough.