When building a degu enclosure, you will often find that only 2 choices are made with regards to doors:
Glass sliding doors in metal or (protected) plastic sliders
Large mesh doors on hinges
There is however a 3rd option. Its cost effective for those people who want a good view of their degus but do not want to fork out for the expense of glass.
An excellent way to view your degus is through plexiglass or glass. Unfortunately plexiglass is not suitable for runners - this is because when you open the enclosure to see your degus, they will occasionally (or frequently!) attempt to chew the plexi. Plexi is not at all resistant against degu chewing so this option is a no go.
I have no pictures of the chewed plexiglass but here is an old enclosure of mine that did use plexi.
The plexi was very wobbly and the degus did chew it, eventually leaving gaps around the edge of the enclosure.
After this I opted for toughened glass, as this is something the degus are unable to chew while the enclosure is open.
Glass is excellent; its sturdy, unchewable and easy to clean. It is however very expensive. Those who cannot afford the glass and are unable to use plexi due to damage will often go for mesh doors.
There is however a third option. Plexiglass does come in varying levels of thickness, for this option you will want to find a thin piece. You could create a frame for the plexi by etching a groove into 4 pieces of wood and slotting them around the plexi to glue it together.
Another option is to place 2 panels on either side of the plexi and bolt the wood together, sandwiching the plexi. You will need to screw the bolt really tight to make sure there are no gaps. Do this for all 4 sides.
This will give stability to the plexi and is much cheaper than trying to install glass on sliders. If you are creating a plexi door you will still need to protect the wood accessible to the degus with steel.
I personally prefer glass but it can sometimes be difficult to slide the glass, especially if its larger. In regards to being able to access the enclosure for jobs like cleaning, you will want to be able to remove the glass from the slider to give you full access to the enclosure. This is something that is not a problem with hinged doors as you can just have them both fully open while cleaning.
Providing detailed guides on how to construct and build degu enclosure, vivariums and cages. This blog has a focus on stimulating and creating more natural habitats for degus...