$450 is kinda cheap for a one-time repair, if it were to motor on for another ten years. It's when you start doing $450 every month that most balk, as you could buy a new vehicle for less. Between those two extremes is when it's time to move on, albeit complicated by one's desires for money/uptime/aggravation. For instance, if you're cheap and can repair in your spare time, you might wait until later to replace. If you can't deal with downtime and you have money to burn, you replace sooner.
For an '06 with such low miles I'd be tempted to repair the door panels, but only if I could get them for less. Up here it'd be showing its age, and I probably would start not spending money on cosmetic issues.