It really came in handy when we spent a holiday in Goa without our luggage ever catching up with us. I didn't have makeup, I didn't have toiletries but i did have my straighteners

I have just watched someone being interviewed who has been trying to fly out of Heathrow for 4 days now. Pretty disgracefully, BA had not given him back his luggage. So- dont let your long awaited holiday be totally ruined for the first few days- be prepared.
By the way- after my Goa holiday I realised that I really didn't need the mountain of stuff I take. Our luggage now(especially with kindles instead of books) is always way below the limit on the way out.