5k I'd think everyone should have it no questions asked. 10K, its expensive but whats it worth to have another set of eyes....
$5K is a lot to most pilots. You go pay for it. If you have a G1000 panel it is about $15K to add it.
A lot of smaller older planes are only worth $15-$25K. You are talking 1/3 the value of the aircraft just to come into compliance. I think most are waiting until the last minute in hopes that a cost effective ADS-B system is developed for their airframe and avionics.
They are also a significant wait and balance issue and the ICAs require frequent inspections on some installations. Not a no-brainer by any stretch.
