technical question about device discovery

hi there!

I have a technical question concerning the bluetooth inquiry process.

I wonder why it always takes a long time (up to 10s) to discover a new
bluetooth device for the first time. after a device was discovered once,
the discovery will only take a few seconds when repeated. even if both
devices are turned off and on again and also if several days are between
the attempts.

what could be the explanation of this effect? are there information that
are cached by the device doing the inquiry? or are the devices
synchronized after the first disovery and keep being so for days, even
when turned off and on again?

If I look at the technical documentation of the inquiry process, no such
potential pre-knowledge is used.

any hints are welcome

thanx,

--luca