I write this advice not as someone who actually took it. Absolutely everyone I knew and everyone who cared about me gave me this advice and I all but ignored it. This is a "do as I say and not as I didn't do when I should have done..." bit of advice.
If you have something on your plate, like an education, a thesis (me!), a class, a project, a dissertation etc. which you aspire to complete, get it done before you take the leap to stay-at-home-dad.
In my case, I had begun a master's degree a few years before my daughter was born and only had to complete my thesis. I put off my thesis for a year before, and then I learned I was going to be a daddy. Instead of dropping everything and finishing my thesis as quickly as possible (it's pass/fail after all), I made little real progress while distracting myself with all the other preparations for the arrival of my daughter. Yes, I spent time writing and reading and note-taking, but at no time did I buckle down and get it done.
For the past two and a half years since her birth, I have struggled to make time and give energy to my paper. After a full day of taking care of an infant (now toddler) and her mother, I struggled to do anymore than read a few pages and take a few notes. We currently have our daughter in day care three days a week just so I can finish it this semester, fully 4 1/2 years after I finished classes.
The mere fact of this unfinished project has hung around my neck like a millstone for the duration of my life as a father. My previous inactivity and apparent inability to get it done made me feel like a failure even as I was succeeding to all outward appearances in taking care of my two ladies. Not being finished with this important project has raised my baseline stress level, and when you add the stress of keeping an infant alive and happy, keeping a wife happy and lively, keeping a home happy and livable, and managing the day-to-day business of happy living... ugh. Let's just say that being a stay-at-home-dad has been more stressful for me than it needed to be. It's my own doing. Had I finished my thesis before my daughter was born, I am sure everyone in this family would have been a lot happier for the past 32 months. When I finally turn in my paper this month, I look forward to a lower baseline stress level, a better self-image, and a happier family altogether. I set my watch and warrant on it.