How often do you race 5k's during training? When is it too much?

I ran the Houston marathon in January and then decided (based on the advice of the lovely people from this sub) to begin training for 5k races. I am currently in phase 3 of daniels 5k program. I'm thinking of doing a 5k TT this weekend at a local parkrun. I was wondering what the sweet spot is for racing/training. How often should I race a 5k? My mileage is about 40-55 MPW.

It seems from the Daniels book that there are many who race weekly during phase 4 but that is likely for college kids.

What is your age, mileage, background and how often do you race 5k's during your training blocks that are 5k specific?