My primary focus is on building lines with high experience multipliers and strong genetics. Sometimes I breed for nice colours because it's fun! For the extra challenge, I never inbreed.
All of my males go up for stud when they reach level 40. If locked, I'll unlock him upon accepting a breeding request, unless I see that your female is not ready to be bred. My stud prices are affordable and are based off of a formula that takes into account the dog's experience multiplier, litter size gene, and HH count. The breeding level is usually set at level 20. I rarely reject breeding requests. If I do reject a request, it's typically because the female has been bred many times previously (as multiple breedings drastically reduce litter quality). I often have females available for public breeding as well, though they are priced higher.
I occasionally have litter puppies or achievement dogs for sale. If you buy one from me, I won't keep tabs on what you do with it, though I'll be happy to buy it back if you ever no longer want to keep it.