Crate sizing is the detail most likely to undermine crate training if it's wrong — and the common instinct to buy generously oversized works against the crate's actual purpose.
Right-sized, not oversized
A properly sized crate lets a dog stand up fully, turn around, and lie down comfortably stretched out — but not much more room than that. This isn't about minimizing cost or space; it reflects how crate training actually works: dogs generally avoid soiling the area where they sleep, and a crate that's properly sized leverages that instinct for house training. A crate that's too large gives enough room for a dog to use one end as a bathroom and still sleep comfortably in the other, undermining the entire house-training benefit a properly sized crate provides.
Growing puppies need a plan, not just a bigger crate
For a puppy that will grow substantially, buying an adult-sized crate immediately means it's oversized during the exact training period when correct sizing matters most. Many crates sold for this situation include a divider panel, letting the usable interior space be adjusted smaller now and expanded in stages as the puppy grows, avoiding the choice between buying multiple crates at different sizes or living with an oversized crate throughout puppyhood.
Wire, plastic, and soft-sided crates suit different needs
Wire crates offer the best visibility and airflow, generally collapse flat for storage, and are easy to clean, though they offer the least den-like, enclosed feeling some dogs find more calming. Plastic (often called "airline-style") crates are more enclosed and den-like, required for most airline cargo travel, but bulkier and harder to store when not in use. Soft-sided crates are the lightest and most portable, good for travel or temporary use, but offer the least security and durability, and generally aren't appropriate for a dog that chews or scratches at confinement.
Crate training is a gradual process, not an immediate solution
A crate is a tool that supports training over time, not something that works simply by placing a dog inside it. Rushing the introduction — extended confinement before a dog has had positive, gradual exposure building comfort with the crate — often creates anxiety and resistance rather than the calm association crate training is meant to build. This is a training and patience factor more than a product feature, but it affects whether any crate, regardless of quality, actually serves its intended purpose.
The one thing people forget
Never leave a collar with dangling tags or a loose leash on a dog inside a crate — both can catch on crate bars or gaps and pose a real strangulation risk if a dog moves around or tries to get free. A properly fitted collar with no dangling attachments, or no collar at all while crated, removes this specific and genuinely serious hazard.