One common disadvantage of having a small dog door is that the animal grows but the door does not. Same as if your pet gain weight, it would be difficult for the pet to use the door.
There are many different products on the market that are used on doors to allow pet to go outside. A product like Staywell Pet Doors serves to allow pets to go outside when needed.
A pet shop, or the website for a pet shop would be the best place to purchase a doggy door. Some websites even specialise in just pet doors, for example Pet Doors Online.
There are various places that one can buy or purchase pet safe dog doors. These stores include but are not limited to, Amazon, PetSafe and Petco. The prices however vary from one store to the other.
Petsafe is a company that markets and sells multiple types and sizes of pet doors including doors for dogs. Large pet stores such as Petco that have an online presence may sell Petsafe dog doors. Amazon is also a source of Petsafe dog doors.
Some disadvantages of using a pet crate over a pet bed is that the animal may resort to hiding in the crate and using it as a safe zone when scared, which could be a bad habit for an animal.
Generally, pet doors are made of a highly-durable plastic. Some may have wooden frames for mounting. Others come with aluminum frames. The best will come with a hard plastic door that will lock into place after the pet goes through it.
There are instructions on how to install all kinds of things from pet doors to windows at stores such as Home Depot, Lowe's, or Menard's. You can probably also find them online.
Brick and mortar stores that sell Staywell doors are Petland and America's Pet Store. You can also find them online at both of the previous stores as well as directly from the manufacturer.
The cost to install electronic pet doors depends on the size, placement and features. This can vary from 150 dollar to 350 dollar. People can choose for a wooden or glass door.
There are many companies that manufacture dog doors that can be used with sliding glass doors. Examples of companies that manufacture dog doors that can be used with sliding glass doors include Patio Pacific and Pet Door Guys.
I have seen the doors advertised on the Home Depot website and in Lowe's. You will have to look under patio and outdoor doors in order to find it.
Visit pet shops such as Petco and PetSmart. You can find all sorts of pet based accessories at those stores. You can also probably find some cat windows and doors at Lowe's, Ace Hardware, and Home Depot.