I've made it five days so far. It was brutal at first, especially with the sunny weather (which is otherwise welcomed), but I've gone faster and felt stronger with every outing. I'm really hoping I can keep this commitment, as the physical and emotional benefits are many and the drawbacks few.
My current plan is to keep up the 3.1 mile/5K route until I can do it in about 34 minutes (11 min/mile pace), then start adding a longer run one day a week, building that run up to 6.2 miles/10K. And that's it. Other than Bay to Breakers (7.46 miles/12K), I am not doing any more runs longer than 10K. And I'm only making an exception for that one because it's a local tradition and next year will be the 100th running of the event. Almost every time I start going longer distances, I get injured, sick, or discouraged, and end up not running at all for months.
I hope to start competing in 5K races again starting in January. My ultimate goal is a 30 minute 5K; closest I've come is 30:30 back in '99 or so. I'm a naturally slow runner and I just have to accept that I'm doing this primarily for my health and not for the competition, but having a race to look forward to does help keep me motivated.