The time usually comes when those tiles are old and leaky and do nothing to make your home look good or keep its value. It is time for re-roofing but what material should you choose? Staying with tiles will eventually give you the same problem that makes your home look rather old and awful right now; namely, mould.
This black growth over your roof is one of the major problems of tiles. It is hard to remove and often keeps coming back. This is because the roots penetrate into the tile and cannot be scrubbed away. After you have gone to the cost or time of having it all washed down and treated it will end up back on your roof as bad as ever.