It all depends on the strength of dog you are fighting...... If you fight a very strong dog your experience shoots up fast
If you are chicken and fight little wimps it will take you until you are as old as tealeaf to make any progress.....
My dog is not very high on levels because there aint many stronger dogs for him to try against
.. But my son JOSH got his up so high by fighting my max a lot..
As your levels go up you get extra strength, health, defense and agility all for free
Without spending any money you can get to level 100 and strength etc in the thousands for free
If you do it right ..........
So just fight like crazy people