This is worth a chapter in its own right; maintenance of especially bikes but also other gear is something you are dealing with constantly. Here is a basic list:

Tyres, Tubes, Patches,  Cables, Brake Pads, Spokes, Chain, Rear Derailleur, Lube, TopPeak Alien Tool, Vice-Grips, Hyper-Cracker, Nuts & Screws, Superglue, Cord, Nylon Patches, Cordura,

Continental Town and Country are what we use and have seen what other people run on and haven't been persuaded to change. They are not perfect but they are about to become so with a kevlar sidewall which will make the rest of the tyre as indestructible as the tread.

Tubes may seem a funny thing to get particular about but they take a lot of punishment and you don't get far without them. Michelin make a really chunky heavy duty which and we carry a half dozen spares, enumerable patches and a dozen tubes of glue.

Miscellaneous spares include a couple of brake and gear cables and half a dozen sets of brake pads each, a dozen spokes each (have them cut and threaded so all spokes fit all bikes) and a half dozen links for each chain. We also carry a spare derailleur since, although we've never had use for it and it's heavy, we'd be stuffed if one broke (which they can do). A simple thumbshift is also useful if one of the speedshifters fails.

The bikes have to be lubed every day. We've tried several different sorts ... Triflow (too thin for chains but good for cables); White Lightning (useless, it's mainly water); Aerosol motorbike chain lube (unnecessarily sticky and requires regular cleaning); SFR - the ideal lube, we used 45ml in five months.

Three tools will do everything we are likely to encounter on the road, an Alien (which has everything from a chain tool  and tyre lever to a spoke key), a pair of small (genuine) Vice Grips and a HyperCracker (essential for changing spokes). A knife tool is something we carry anyway and a needle and thread (awl size) is handy.

We try to keep all the nuts on the bikes the same size but it's impossible. We carry a range of spares of these with locking nuts. High tensile is better than stainless steel. Loctite make superglue in a 20ml bottle. A couple of hundred metres of 1 & 2mm cord in ten metre lengths is good for pitching the tent and binding broken things (smothered in glue a whipped section is a strong as it ever was). Nylon patches are for clothes, the tent or sleeping bags. The cordura is for when heavier repairs are called for.