Yes generally i reject any request if its customization just for one customer. I try to generalize the change by e.g adding an API call. Also i get requests to keep xp/win7 support which i reject often.

The biggest thing I learned is to basically do nothing on the product, unless its needed. I used to be tempted to change things/add features for fun and for a challenge but its a mistake. The reason is it might introduce bugs. Too many customers and big companies rely on virtualhere now day-to-day and the software is complex enough that its hard to tell if the bug was always there or just from the new addition. Im very relucatnt to even upgrade the compiler unless i have to for a new OS etc.