I had a 55 gallon tank and the center brace broke. I thought nothing of it until I noticed the glass bowing out. A quick check with fellow aquarists on a different forum made me realize that my tank was in imminent danger of breaking apart. I did a quick tank swap (and upgraded to a 90 gallon) and dumped the old tank.
Could the old tank have been repaired? Probably. By me? No.
I live in an apartment and can only imagine the amount of damage that 55 gallons of water would have done to a wood floor. For me, it was worth the time and expense of a new tank.