Lost luggage

The luggage is missing. Rover and contents are having an adventure all on their own but it leaves me with a dilemma.

How much stuff do I go and buy - underwear, new clothes, suncream, toiletries, Ipod recharger, unread books? Where should I stop. I am not sure that I covered insurance wise as they only pay for delayed luggage on the outward journey which technically I am not on - but then I am not on the return journey either but then they will cough up if it is lost entirely.

If I buy stuff do I buy a case to put it in because if the original one turns up then I can't take them both on board as you are allowed one case and it is a different airline to the one that lost the case - unless I go and explain and they are being nice.

It is annoying and irritating but no doubt will be sorted or not. I have been on I supposed it was bound to happen sooner or later