Full Use
A pilot I worked with many years ago was an ex Navy carrier pilot.
On carriers you use the full length.
When he started flying commercially he told be the runway behind on take-off is no good when things go wrong so always use the full length.
From what i understand the CAA made a recommendation a couple years ago about light aircraft with retractable undercarriages not to raise the gear to early on departure as on some runways you could land back on if there was a problem on take off.