We have an older home that has only one bathroom. Is it worth the cost to add a second bath? Having one bathroom is not a problem for us. I am thinking of value added when we sell the house.

If you add the bathroom yourself, then it would be worth the cost. Having a contractor do it would be questionable. Alot depends on the value of propety in and around your house. Trying to recoup a $5 to $15 thousand dollar investment is not easy.