Nothing wrong with that. I always look at things this way. What do I make an hour, what would it cost me to have someone else build it? If the numbers work out that I am wasting my hours (and have to be away from work or my kids to do it), I would usually farm it out. That being said, I am building a keezer, with a kit from Keg Cowboy, I just wait until the kids are asleep and I am off work to do it. At that stage, it is worth it to me.
PS: 5 lbs last 5 corny kegs is what I have been told.