I have lost my luggage several times in the past at the airport and this has taught me a great frugal lesson.
Never buy expensive luggage.
Instead I but second hand cases from a boot sale or yard sale and as long as all the locks work and the case is secure, I find they work great for my travels abroad. And if they get lost well so what, I still claim on my insurance but the loss of my actual cases no longer bugs me like it used to.
My other tip is to buy cases which are very distinctive. Add big coloured labels to them or use stickers on the bags. This makes it not only easier to spot when you are collecting them but also makes it more difficult for anyone to try and steal your bag, as it is so recognisable. Thieves tend to target either expensive looking bags or ones which are non descript.