I think a better question to ask is "why should I start a dev log?"
Are you trying to use it to market your game? Does this mean you're going to sell it commercially?
Are you trying to share developer insights into game production?
Is it just a "requirement" you think you need to satisfy to launch your game? (it isn't)
I've done dev logs about my own game development and one thing I've learned is that it takes a lot of time to write them up. Even on a monthly basis, it can take a whole afternoon -- which could be spent making the game instead. Choose your dev log frequency and length carefully