At 15+ weeks, a mile or so plus playing in the yard and/or the house keeps Lisl content.
Some days we do more and I can tell it takes more out of her. I try not to exercise her so much that she naps more than 20 or 30 minutes when I'm home. I don't want her up all night.
The days I work we have to do more because she spends sometimes up to eight hours in her crate. We walk about a mile in the morning and then again when I get home, plus playing in the house and training.
It's a full time commitment but she's worth it.
Bear, Anna, Molly, Ossie, and The Countess Lisl von Schlaf
An Unhappy German is a Sour Kraut!