Scratch resistance is very important when selecting a tile. If a tile has a low scratch resistance, it will look dull and worn in no time. Moving furniture or appliances may scratch the floor or simply regular cleaning. Some natural stones are softer than others, so be sure to do your research before you choose.
Thickness of the tile must be considered. Thicker tiles are usually stronger and therefor can resist high impact from dropping heavy object on them. Thick tile may also cause problems with height restrictions with doors and mouldings.
Colour and tone of the tile may make it look dirty too easily. This also applies for grout. Light grout may look dirty and change colour very easily if not properly sealed. Too dark or too light may show pet hair or dust very easily and it may seem impossible to keep up with the cleaning.
Water resistance is key in wet areas. Avoid porous tiles in showers and pool areas. They may easily stain and hold moisture that can cause mould issues. Sealing can help this but must be done regularly to maintain resistance.
Size must be considered when choosing tile. Many people like large tiles on their floors. This is a great look and has less grout lines to clean. Larger tiles require flatter and more rigid floors in order to make them work properly. If a floor is not flat it my need to be built to where things will be true. This may cause your new tile floor to be much higher than your other floors in your home. You must also consider structural conditions. Minimum code floors in most areas are not rigid enough for larger tiles and the deflection may cause cracked grout and tiles or loose tiles. You may have to do some structural work before you install large tiles. Small tiles require more grout lines and they are harder to clean. Grout is also a way for moisture to get behind the tile, causing problems. Be sure to choose the best tile for your situation.
Grout is also something you must consider for your tile. Larger grout lines may be harder to clean but will be more forgiving with the variance in tile size. It allows the installer to "cheat" when things are not lining up properly. Smaller grout lines (1/8" or less) require an unsanded grout which is not as strong as a sanded grout.
A quality tile supplier and your contractor can assist you in choosing the best tile for the job. Sometimes you may not get the exact tile you want because it will not be the most practical. Choose something that will last and does not require more maintenance than you are willing to do.