I must be paranoid about getting a flat or breaking down. Despite being an AA member, I feel uncomfortable and insecure about going anywhere without the following items packed in a stuffa bag lashed to the rack.
1/ Electric air compressor.
2/ 9 inch 2 way cycle pump (should the above fail). Useful for adding a lb or two when checking pressures.
3/ Pressure gauge.
4 / Puncture repair kit with a few extra large patches & some talcum powder.
5/ 2 x 10inch tyre irons.
6/ Sockets and wrenches suitable for wheel removal.
7/ Small bottle of soapy water - to find leaks and aid tyre removal/fitting.
8/ Hand cleaner...also useful for tyre fitting.
I also use "Ride On" puncture preventative and carry a mobile phone to call the AA if necessary.
Next job - Seal the spokes when new tyres are due.
Boy Scout's motto - "BE PREPARED"