How do you know when it's time to replace a fish tank?

[lockrookie]

possible but not likely water will find the weakest point and the tank will begin to leak before it falls apart. ive had a tank spring a leak of course in themiddleof the night murphys law... the silicone you se in the corners is not the only thing holding the tank together it help definately but the glass pieces are also stuck together on the seams to hold the peices together.. trust me i have taken enough tanks apart to know its can be difficult to separate them. as i say my view is this if you have cause for concern be concerned and dont ignore it either buy some tubs drainn the tank reseal the corners once cured refill (preferably add new sand) and your good to go. or if you have scratches and other things you dislike with current tank use itas a good excuse to findyour watery riends a new home get new tank built/set up and transfer your water(preferably new sand) to new tank and rock and your good to go.