If your puppy is small and low energy, this pen will be perfect for you as is. If your puppy has limitless energy, read this to hear about how we modified the pen to work: We first got this pen right before we bought our goldendoodle (Rowdy) home. We live in a high-rise apartment building smack in the middle of a very dog friendly city. Since Rowdy hasn't had any of his shots yet, he wasn't allowed to go outside to places that other dogs might have gone to the bathroom. That's pretty much everywhere in this city, so it ruled out us being able to bring our puppy outside to go potty. Using an 8-panel pen with a litter box ( Bunny Wonder Plastic Dropping/Litter Pan for Pet, 24 by 24-Inch ) was the perfect solution until he was at least old enough to go outside or hold it through the night. It also prevented us from having to get up in the middle of the night to take him potty since he wasn't ready to start crate training. First, Rowdy has a lot of energy. Like, boundless energy. If your dog is smaller and isn't supposed to be very energetic, then the unmodified pen should work perfectly for you! I work from home and play with him for 15 min almost every hour, by the end of the night he's exhausted and by no means neglected–he just seems to enjoy the challenge that escaping provides. Looking at the height of the sides, we figured it would be a few months at least before he was able to escape. Wow were we wrong. The first escape happened about two weeks after we brought him home when Rowdy was 10 weeks old. We heard whimpering at the bedroom door and walked out to find he'd escaped from his pen. The walls of this pen have a bit of a give to them, and when he ran up against the corners quickly, the side of the pen would bend just enough for him to sort of scale it and climb out. Our next attempt to keep him in was inspired by one of the other reviews here. We bought that green plastic fencing that you use to keep deer out of your garden, and we secured it across the top, leaving one side done up with velcro so we could undo it and still scoop his litter box. See one of the photos attached to this review if you don't know what I'm talking about. At first, Rowdy could sneak his way up through the corners, so we secured those extra tight. Although this was quite unattractive, it worked for a while– probably about 4 weeks. Then, Rowdy started teething. While we were out running errands or sleeping, Rowdy would be jumping up and chewing through the plastic cover. We added another layer of the plastic fencing so it was double-layered. Finally he chewed his way through two layers of plastic and we realized we needed a new solution. We have now made many modifications to the pen and have finally found one that works and isn't a complete eyesore. We removed two panels from the pen and placed them on top of the six panels, one side is zip-tied down and the other we velcro up when we're leaving him in there. So he can have a little more room in there, his crate ( AmazonBasics Double-Door Folding Metal Dog Crate - Medium (36x23x25 Inches) ) is attached to the door of the pen and he enters and exits through the other door of his crate. Sorry this isn't a great description, but I've attached a few photos of the end result. Although he's now fully vaccinated and we can take him outside to go potty, he's still only 4 months old and we'd prefer to not walk down our apartment stairs every couple hours to take him out. He also now sleeps peacefully through the night, with access to his litter box if he needs it. If we leave him at home for extended periods of time, I'm no longer worried about him escaping this fortress that we've built and having accidents all over the apartment. Giving this pen 4 stars as I feel that, for the cost, the sides could be made with a little less give or at least with a way to lock them in place. We now have two of these, a white one and a gray one. The white one we use to block off the rug in our living room as we couldn't find a normal gate long enough, it works perfectly for the purpose. I hope this review was valuable for anyone else that also has an energetic puppy. Having this info when we first got the pen would've saved us a lot of time and energy and I hope it helps you!