Blog commenting makes you tired?

Are you doing blog comments recently, for a number of blogs? For me, this is one of the difficult and exhausting jobs I've ever known. Most webmasters are usually relying on do-follow blogs, so it's not easy for me because there are only less than 10% chance that you can find a do-follow blog. More than 90% chance are no-follow and dead links because they don't want spammers to just spam their blog and gain backlinks from their site. They would insist that spammers only destroys the image of their topic, likewise their whole blog as well. Last time, I just bought from someone at DigitalPoint on his complete list of do-follow blogs which are auto-approved, most of them are EDU and GOV sites. We can only buy do-follow blogs from the experts, but I think there's only a slight chance that we can see do-follow blogs for free.