Two choices you are going to have to make about which sofa you end up buying are, what size of sofa you want and what material and colour you want the sofa covered in.
Probably the type of material covering and the colour you have are the biggest and often the most difficult choices to make. But hold on, before that there is yet another serious consideration to make! How durable does your sofa need to be? Is it likely to get grubby from children, pets, food and sofa covers drink spills? If you are going for a light, plain colour then this is certainly a consideration. Some fabrics are also quite delicate and will soon wear thin in high contact areas such as the arms.
So the first choice really is ‘fixed’ or ‘loose’ covers. There are benefits to both options and some limitations as well.
Fixed Covers; with this type of cover the fabric of the sofa is fixed to the frame and is not designed to be removed as their name suggests. Sometimes the cushions with these sofas will have covers than can be removed but you need to check how they can be cleaned, often they will be ‘dry clean’ only. There is usually information supplied with the sofa about the care of the fabric, always read it first. The advantage however of the fixed cover sofa is that there is usually a much larger range of fabrics available from soft velvet type materials to hard wearing man made fabrics and of course leathers. The fixed cover also lends itself to more shapely designs as it follows the contours of the frame and cushion shaping. High wear and soiling areas like the arm rests can have separate covers on them that are washable.
Loose Covers; these are what the name implies, looser fitting fabric covers that are designed to be removed from the frame of the sofa in order that they can be machine washed or ‘dry cleaned’. Usually on the machine washable covers the fabric is 100% cotton and therefore you don’t get the same range of styles and textures as with fixed covers, nor the tight, shapely contours of the frame and cushions. As with any item of material that you wash, it can over time fade slightly from its original colour, so it is good practice to wash loose covers as a set (frame covers and cushions) so that any change in colouring is constant throughout. In order to alter the whole appearance of the sofa or just to make cover washing less of a time critical process, you can often order a second set of loose covers at the time you purchase the sofa. Although this is not a cheap option, it does extend the cosmetic life of the sofa and is almost a must for sofas bought that are going into furnished, short term let property, where a clean, new looking sofa is expected several times a year.