I like to have date and times on photos reflect local times and date at the location. Unlike another respondent, I like to be able to search for a photo taken "at about 3pm on the Thursday afternoon when I was in Xian" and, while there are other ways of cataloguing and ordering, being able to search on local date and time is a bonus.
Travel from NZ involves long international flights (8-12 hours typical range unless going to Europe.)
I (try to remember to) change the camera date on the flight and change my wristwatch at the same time and take a before and after photo of the watch sequentially so I have a visual reference to the actual time of change in the photo stream.
Outbound from NZ the camera steps back in time so some photos will be out of time/date order. Making the change early in the flight minimises the impact if I care. e.g. China is 5 hours behind NZ and is ~ 8-10-12 hours flight time (Hong-Kong / Shanghai / Beijing) depending also on route so the time impact on photo date-sort order is usually minimal.
In the past I used to assign a long file name prefix based on properly time ordered date. Effectively YY MM DD HH SS in compressed form. It was useful but not so much so that I kept it going.
Fixing corrupted file date & time: Due to Microsoft's cavalier handling of file date & time format when copying from cameras to hard drives you can find time offset by 12 hours and date by one day or both, on occasion. Confusing day and month is another sometime Microsoft speciality due to NZ using ddmmyy format as opposed to the usual US mmddyy format. Use of an EXIF to file date-time copying program fixes this. I use the excellent free jhead program to do this. Running
jhead -ft *%1*.jpg in a [gasp!] DOS batch file will correct the date time to that shown in the EXIF for all files in a "folder". I believe that Microsoft Powertoys synch manager does this too but I have never tried it.
Travelling backup: I use the venerable and marvellous XXCOPY to incrementally copy in files from camera card to a netbook. When in tourist mode I carry the netbook everywhere and may download from camera card several times during the day. [Just because you are excessively paranoid about data loss it doesn't mean your cards won't fail :-)]. When XXCOPYing I change the archive attribute bit in the process, so that uncopied files can be identified, thus allowing an only-new files download incrementally AND leaving a backup copy on the camera card. I then copy from netbook to portable hard drive (possibly also during he day) and only then, if required, delete files on camera card. [On one journey I lost two of my 3 copies of photos (vanished with no clues, probably stolen) and still lost no photos.
The following simple batch files has proved so useful for a decade or few that I offer it here 'warts and all'. I use a 2001 (!) version of XXCOPY for various reasons. Newer versions may or may not behave identially.
By (manually) ensuring camera cards have non overlapping date based folder numbers (xyz) the xxcopy suffixes xyzymmdd to each copied file and so allows folders with otherwise apparently identical file numbers to be distinguished - occasionally this saves files which may otherwise be overwritten or not copied. As the folder ID also includes a date time spamp it allows ALL my files to be unique when using multiple camera cards and multiple cameras - even if I swap cards between cameras during a 'shoot'.
It has done very well for me. It transfers all uncopied files from camera card incrementally, clears the attribute bit on the source (and destination) and appends folder ID and date-time stamp to the copied file name.
/SX - flatten subdirectories - add xyzymmdd before suffix.
/M - copy if A bit set, reset A bit.
SOME (very few) cameras only do NOT set the A bit for new video files. DO CHECK.
All cameras I have so far encountered do so for JPG and RAW files.
rem Usage: SUCK DRIVE
rem Inputs Files from DRIVE with Attribute_bit_set to current directory
rem A: is copying target
rem This program is called with current dir = copying target
SUBST A: /D
SUBST A: .
rem %1 is source target drive
if not exist %1:\DCIM goto NoDrive
- rem Others MAY not want.
rem Clear attribute bit for files in unwanted %1:\avfinfo
attrib %1:\AVF_info*.* -h
attrib %1:\AVF_info*.* -a
xxcopy /bu /sx /m /nx0 %1:\dcim*.j* a:\
; Any files in DCIM not copied are deemed RAW.
xxcopy /bu /sx /m /nx0 %1:\dcim*.* a:\RAW
xxcopy /bu /sx /m /nx0 %1:\MP_Root*.* a:\Video
rem ALL files on source with attrib still set are now copied.
xxcopy /bu /sx /m /nx0 %1:*.* a:\Other
echo No drive with %1:\DCIM directory found