I work at a dressage stable, its true that you cannot use bandages in competition, but to prevent injury and strain during schooling, most people like to use a full set of bandages and possibly a full set of bell boots. Instead of using bandages it is sometimes easier to use excercise boots. There are plenty of good quality brands out there but I preffer to use "10 minute box" which are a simple neuoprene boot with velcro attachments.
Polo bandages can also be use but I find them quite bulky and can sometimes be difficult to bandage with.
For jumping the obvious prefference with showjumpers is to use an open front boot, which is usually attached with velcro or a thin buckle/strap, with a small ankle boot on the kind legs. These prevent harm from knocking and brushing whilst still allowing the horse to "feel" a pole when it makes a mistake!
I hope this helps, Cheers!