Thread about working on a single product for too long :

1. You get to know the product in and out totally. you will know what features are on the roadmap, what can be improved, what will work for the future, what wont, etc. But, any random person outside of the product circle will 'definitely' have an out of the box idea that you've never thought of. keep your ears open.

2. you know all the design styles, you maintain a perfect style guide, you stick to the rules for all new features.