In fact there is no
legal requirement to have a check out flight, if you are licensed for the type you can just jump in and fly it. Depending on type and your experience it normally makes sense to
have a checkout, and even if you are well experienced you should at least read the a/c manual if you can (I have flown a few vintage/homebuilt types that have not come with any manual and not even someone that I could get a briefing off, but I would say I have the background and experience to do this - but even then I would
prefer to do it with checkout, manual or brief).