WellyFlation

Wellington boots are really indispensable.  They turn even the most timid city-dweller into an all-terrain vehicle.  But they are bulky and - if worn for a long time in hot weather - sweaty.  Also, they are not as comfortable to wear as shoes, particularly for extended walks.

Galoshes - that is foot-shaped plastic bags that go over ordinary shoes - go part-way to solving the problem.  You can deploy them just when you have to ford a stream, and wear comfortable shoes for the drier parts of your journey.   But they are not so good for riding horses or climbing - things that can be done in wellies (they have heels, which you need for riding).

So how about inflatable wellies?  These would be much lighter than conventional wellies, and - when emptied of air - would roll up and fit in your pocket.  But if you blew them up they would aquire sprung thick soles, and reasonably stiff calf-gripping sides.  A highly fluoridated outer polymer surface could make them very non-stick, so they could easily be rinsed off before rolling up and putting away.

And if the stream being forded turned out to be a little deeper than expected, they would make an excellent buoyancy aid, though at the wrong end until taken off and slung round your neck...