Whether it's a desire to be outside, interact with whatever's at the window, warming in the sun, or just watching what's going on, indoor cats are naturally drawn to spending time at the window.
Here are some things you can do to make it safer for your cat and more enjoyable for the both of you.
This is not about protecting your windows but protecting your cat and it has to do with open windows.
It may be that you have an indoor cat that you don't want getting out. Worse, you may live in an upper story apartment or condo in a high rise building where your cat could fall or jump out.
Ask yourself whether you feel the screen in the window is sufficient to keep your cat in and what you can do about it if it isn't.
The easiest solution is to simply keep the window closed or don't open it all the way.
Some windows have a feature that allows you to lock the window in a partially open position. If your window doesn't have this feature then you can look into buying a window stop or lock that works with your window. They're inexpensive and easy to install.
If the screen frame is solid and securely attached in the window but you don't trust the screen mesh to resist your cat's claws or be strong enough that your cat can't push through it then you can replace the screen mesh material with pet proof mesh.
How do I replace screen mesh with pet screen mesh?
You may also consider a window safety guard that keeps your cat from leaning directly against the screen.
Cats will find their way through window watching impediments such as curtains or blinds, often making a mess of things as they do so (just ask those who have lost security deposit money or had to replace the blinds after kitty made a mess of them).
If you don't need any coverings on the window then simply remove them. If you do need coverings then find something your cat won't be able to tear up (watch the video below for suggestions).
Cat's are often curious about what's going on outside. If you have wide window sills or a glass door then your cat's probably hanging out there already or at least sneaking peeks from time to time.
However, sometimes your cat doesn't have a comfortable place to window watch.
You can create a perch to give your cat a more comfortable and safer place to look out the window. A perch also encourages your cat to use that window in particular.
A piece of existing furniture that is the right height and width placed in front of a window can be a simple no-cost solution. You could also place a cat tower or cat tree in front of a window.
Another option is to buy a perch specifically for the window. They generally attach to the window sill or the window itself.
Window sill perches
Many of these perches attach directly to the window sill with screws or hook and loop (commonly called velcro) while others hook into the window frame. Check the specs on the product to make sure it'll fit the window you have.
Some perches simply create a wider surface for your cat to sit on.
While others offer more of a bed.
There's also a heated version of the above product to further entice your cat to use it.
You could also get a version with a bolster for your cat to lean against.
Window attached perches
Besides window perches that attach to the sill there are also window perches that attach directly to the window using suction cups.
There are also perches for multiple cats.
Some perches can give your cat an extra sense of security by adding an enclosure.
Two Level Window Perch w/Enclosure
If you have a larger, sturdier window such as a sliding glass door, you may even want to take it to three levels on the window perch.
Three Level Window Perch w/Enclosure
If you want to be able to close your blinds when the perch is not is not in use then you can get a foldable perch.
Just make sure the window will support the weight of your cat or cats. If you suspect it won't then you may want to stick with a ground-based (i.e., furniture, cat tree, cat tower, etc.) or sill-based solution.
Another solution is a cat tower that stands on the floor but is attached to the window to keep it upright, transferring the majority of your cat's weight to the floor instead of the window.
You may also want to consider making your cat's window watching experience more interesting. For example, you could put a bird bath, bird feeder, squirrel feeder, etc. right in front of the window. You could even attach a feeder to the outside of the window.
If the birds are bothered by your cat's presence you can put some one-way reflective window film on the window so the birds can't see your cat. Just put a piece of the reflective material on the inside of the window cut a little larger than the feeder itself.