Locks, door handles, window catches, hat and coat hooks are probably the most relevant ones to the planning of your bathroom storage. This is a trade where tradition and craftsmanship still play an important part; good locks are still largely handmade, while door handles vary from the cheapest aluminium or plastics to bronze or good quality stainless steel.
As far as your bathroom is concerned, you may be able to have completely new fittings throughout and, if this is the case, there are several matching ranges, mostly made of anodised aluminium. Many alternative designs are available if you are only thinking of the odd handle or bolt, but there is no doubt that a co-ordinated set comprising a handle, bolt, hook and so on will add a feeling of quality to the finished room. As with many other aspects of the building industry, it is necessary to take a little extra effort to get what you want, rather than being fobbed off with whatever your local supplier has available. It is a good idea to use aluminium alloy hinges, for example, if your door is to be polished or varnished, and special washer hinges add to the smooth action of the door.
You should also choose the types of a bolt to be used carefully. There are several designs available that not only indicate whether the room is occupied, by word or colour symbol, but also allow the bolt to be operated from the outside by using a special key or, probably more sensibly, by using an ordinary coin. Any parent who has had to try from the outside to instruct a panic-stricken toddler how to unlock the loo door will appreciate the sense of this device. Hat and coat hooks with rubber buffers to act as door stops are also useful. Sliding doors, which are frequently aids to compact planning, pose particular problems with door handles and locks, the normally recessed handles being particularly awkward to use. It may well be better to incorporate a special feature such as a purpose-made handle and door stop running the full height of the door and thus eliminate the standard handle. To lock a sliding door you will need either a hook bolt latch or a patent spring-open bolt, both types being key operated.
Sliding door mechanisms vary from the cheap and just workable to those of Rolls-Royce quality. Choose the best that you can afford; a badly running sliding door is a permanent irritation. Patent sliding folding plastics doors should be viewed with suspicion; they seldom work as easily as they should. The best way to examine fittings is probably to visit your nearest Building Centre, where samples are on permanent display.