I've been taking Bella, 4.5months(ish) lab/greyhound cross, for 2 walks a day. A quick wander in the morning and a longer walk in the evening (30 mins) with time for fetch games. She occasionally gets a walk in the middle of the day with OH but nothing strenuous. The great thing about the walks are they tire her out and she relaxes in the evening giving our cats a chance to come up to her without getting pawed by a hyper dog.
However, after reading a couple of threads I'm a little concerned that I'm setting her up for leg problems in later life. How much walking should a younger dog do? She does have huge amounts of energy and when walks are missed she becomes seriously boisterous.