For me I just want to remember what's gone on in my life better, even if it's sometimes mundane. I've tried short-form daily journaling, but I've only made it around 3 months before I start skipping days and stop doing it altogether.

When it comes to doing something new/memorable, I'd be fine with aspiring for just one thing per month (with the assumption that sometimes/often I'd end up with more than that).

I think the way to make things like this work is to start with a low-ambition target, and then scale up until just before the point where it starts to feel difficult to keep it going. I'm not sure I could keep up a cadence of doing one memorable thing per week. Once a month seems doable, though. But if I were really uncertain, maybe I'd first target once per two months, and then see how much more frequently I could do memorable things before it started feeling like a difficult burden.