Since you've indicated that you are looking at females. Ask yourself this: Do you intend to spay the dog? If not, you will have to deal with the twice yearly heat cycles. The spotting makes a mess, and if there are any males in the area, will attract any and all uncut males to your yard that are within smelling distance of your dog. If you keep her in the house, the blood will get all over everything, and despite your best efforts to keep everyting clean, you will inevitably find that missed spot after it's dried up and stained the carpet, rug, fuirniture, etc.