Why re-seal? Well, once your seal is turning black, it loses some of its integrity and can start to open up which will inevitably allow water ingress behind the seal. Eventually, as the area behind the seal becomes water logged, the water will start to head downhill and more than likely show its hand on the ceiling below (assuming the bath or shower is not on the ground floor obviously). It will be slow at first but the damage will spread quickly until water is literally dripping through.
Once this stage has been reached, the cost of repairs rises dramatically.
The real solution is to be pro-active and re-seal before the damage occurs.
When I am re-sealing baths and showers, I take the utmost care to remove the old seal completely. Having done that, I can tape up the area (as in the picture above) ready for the new seal so that the finish is of only the finest quality. I use only the finest anti-fungicidal mastic sealant too meaning that your seal will have the best new start in life.
I can guarantee that you will not be disappointed with the finished result.
Click Here to see another example.