I'm in the process of taking down a 29 gallon vert that I started cycling in early 2010 for a pair of thumbnails. It didn't get frogs into it until 2011 and had a substrate refresh in early 2013. The GS background fully seperated from the glass but was fully sealed to the glass by silicone. The GS also started to break down quite a bit but the wood was still held solid in place. It could have gone longer but I had a few 40verts well cycled and the frogs got a new home that was much nicer.