2002 Convertible - how long does roof last?

[Shastakovatch]

Hi Everyone! I'm a newbie here. I love my Solara, but recently someone slashed my roof. The 2002 roof comes in two pieces: the top and the rear window panel. I have to replace the top where the slash is, however I'm trying to decide whether to replace the rear window panel as well. There's nothing wrong with the panel at the moment, however in talking to mechanics, it sounds like this panel is prone to failure.

Does anyone have experience with these roofs and the rear panel? I'm wondering how long they typically last? Mine's already 7 years old, and I park my car outside in San Francisco weather. I'm wondering if I'm just tempting fate by not switching out the panel now when the rest of the roof is being replaced. Parts and labor to replace the rear window panel now is $500, which is not exactly cheap. However if I have to replace the window panel in the next few years, I'm sure it will be much more costly.

Appreciate your thoughts on this. Thanks!