It is impossible to buy every tile that one likes so it is wise to set limits, cost is an obvious limit but why not also choose a theme. When starting out it's great to build the collection quickly so choose tiles that don't reach the higher prices. It also means that inevitable mistake isn't too expensive. Tiles are in perfect or mint condition as would be defined by collectors of other ceramics virtually do not exist. Tiles were never intended to be held and inspected as for example a cup and saucer may be, or placed in the display cabinet or on the mantelshelf out of harms way as a porcelain figure would be.
Tiles are more rugged, they are architectural fixtures, built to expect bumps and bruises.
Many of them would be framed in cast iron in fireplaces and wood in furniture so their edges would not be seen. Many if not most Victorian and Edwardian tiles have a factory fault, a chip in the edge of the biscuit that has been glazed over or painting that fails to follow the printed or moulded outline are two of the commonest defects. Whilst some collectors of pottery and porcelain may sneer at the condition that tiles are acceptable to a collector it could in fact be their loss. The fact that the old chip or blemish does not detract from a good tile is a massive bonus. It is easy for the viewer to see through the imperfection and partake of what the creator intended.