Choosing the correct stair-lift

Your choice of stair lift will of course depend on the structure of the building in which you will want to install it. But generally this will fall into one of two types:
Straight Stair Lifts

If your flight of stairs has no bends, then a straight stairlift is for you. As the name implies, straight chair lifts start up at the bottom and go up in a straight line to the next floor up.
If your flight of stairs has an angled bend, perhaps with a half landing, then you will need two straight stairlifts (or possibly a curved stair lift ? your stairlift manufacturer/installer will be able to give you the best advice on this). Some stair cases even have two angled bends with two half landings between floors. In this case you will need to have three straight stair lifts. This will add to the cost of your stair lift.
It is not easy to choose which is the right type of stair lift for your flight of stairs, and expert advice is recommended. A trained stairlift specialist will visit your house and review your staircase.
For obvious reasons, straight stair lifts are easier to build and install than curved stair lifts. If your staircase is standard, you may find that and ?off the shelf? stairlift will suit your needs. Older houses often have non-standard measurements and you should take the advice of your stairlift specialist installer.
If you have a standard staircase, installing a straight stair lift is usually the cheapest and quickest option. However, if you have a non-standard staircase in any way, you may find that you need to have your stairlift custom built. This adds considerable to the cost of setting up a stair lift.
Curved Stair Lifts

Some staircases, particularly in larger houses, are curved. If you have a curved staircase, you will need a curved stair lift designed especially to fit the corners or bends in your flight of stairs. The main disadvantage of this type of lift is the cost. Since the lift has to be custom designed and built to fit your staircase, the cost will be considerably more that a normal, straight stair lift.

Many people consider second hand, re-conditioned stair lifts. However, if you have a curved flight of stairs, you are most unlikely to find a second hand stair lift that exactly fits the curve of your stairs. Therefore there is only a very limited second hand market in curved stair lifts.
Another factor to consider about curved stair lifts is that they are nearly impossible to re-locate. Many elderly people choose to move home when their houses become unmanageable for them. If a straight stair lift has been fitted in the old house, it is perfectly possible to relocate a straight chair lift to another straight staircase. But if a curved stairlift has been fitted, it would be very unlikely to find another house with exactly the same curved staircase.
Another disadvantage of curved stair lifts is the servicing costs. Curved stair lifts often require more servicing as the nature of the construction (curved rails and tracks) means that additional stresses and strains are put on the stair lift. If your staircase has a flat landing half way up, it may be best to consider two straight stair lifts rather than one curved one. It depends of the curve of the wall of course. If the wall is curved for the entire length of the stairs then it would not be possible to have a straight stair lift at all.
As curved stairlifts are custom built, and require a more complicated manufacturing process, they then to be much more expensive than straight stair lifts. Often two straight stair lifts to a half landing is the cheaper option, although this is not always possible. It depends on the construction of the staircase