Your blogging will have an ROI, even if you spend 10 minutes a week. Of course, the return will be proportional to the investment.
A client who has been blogging for about a year recently emailed me from the east coast. He is on his first very lucrative consulting gig that he can directly attribute to blogging. Tom writes about one blog post a week.
Another client, Mike, who has been blogging about 8 months just landed a consulting contract in Manhattan. He says that he would never have gotten the contact oif not for his blog. Mike writes a new blog post about every other week.
Two examples very close to home that blogging boosts your image, exposure and revenue without giving up your life.