Improving security on glass

[3Point5InchFlop]

I'm focusing on the kitchen, and the problem is glass!
I've got 2 windows that can be stepped through as the deck is raised and I've got a UPVC door.
I cant afford to replace all windows right now so I've been looking at adding security film to the glass. Has anyone done this themselves? Is it easy to apply?
The videos speak for themselves when you watch someone try to bang them in, and I know the big stores have it fitted on their glass, seems a good idea.
any tips or advice?

 

[Maccapacca]

If it's not done properly it'll look terrible.

It's probably the best idea and not looking like a prison

 

[LiGhTfasT]

Did 2 massive windows in some internal french doors. Ended up putting the backing film on and binning the real film by accident on the first door, it did look perfect though. When i put the right film on the second door it went on just as easy.

Need to get some more to finish it off, you can tell by tapping on the glass its a lot more rigid.

Not hard to do, i just used a squidgy and fairy liquid and water in a spray bottle.