Starter or Ignition switch?

[DaveBMW]

Purchased 2005 x5 4.8iS on Saturday. Everything cool in NYC (of course). Drove to NJ/PA line, stopped for gas.

x5 would not start. No crank, no clicks, nothing. Dash lights all looked great. After poppin the hood and checking around jumped in and started up.

Ran fine, stopped near home. Came back 2 hours later, started normal. Drove home and parked. Sunday afternoon, first time tried to start since parking the night before, and..

x5 would not start. No crank, no clicks, nothing. Dash lights all looked great.

I did not bother popping the hood or anything, just came back five minutes later and started right up.

Started multiple other times that day with no issues.