Depends on the event mate
Time card enduro's are usually F.i.m marked tyres (eg metz six days,etc) not seen a noise tester yet!
Some but not all require you to be legal as some have road work involved in them.
H&H are a lot more relaxed no road work and 99% they let mx run sometimes in separate class
Basically a time card enduro is a timed event were by you are let off the line in 2,s or ,3s with specific times marked on your card to reach check points, If you arrive at your check point early then all the better have a rest then go through the check at the time marked on your card,go through early and you will be given penalty points
On the other hand if you arrive late at a check,you must add the time that you are over to your original time at your next check! sounds confusing but it get's your brain working,during the lap there will be at least one special test which you are timed through from start to finish
In the event of a tie with another competitor the winner will be decided on your special test times (ie fastest through the test)
Some of these enduro's are 5-8hr events depending on class and how fast you are!

H&H events are basically a motocross race on steriods (Flag-Flag)Held over anything from 1hr-3hrs
Varying terrain anything from mx tracks to deep deep bogs,Quarrys,woods bit of everything
H&H events are *Normally* suitable for all ability's from novice to champ riders
Some are technical some are fairly flatout and boring
Will not involve road work so you can race pretty much anything
If your new to offroad most will find anything this time of year fairly hard going due to the ground condition's!
Hope this helps a bit
Andy.