Sylvia,

While it is customary to use separate controls for entering date and time (because of the variety of formats) - it is desireable to store date and time in a datetime field for the following reasons:

1) it is more compact - a datetime field requires 8 bytes while a date field alone requires 8 bytes.
2) you can perform calculations on a datetime field which you can't do if the time is stored in a character field.

Take the time to program your form to split a datetime variable up for your calendar and time classes and put it back together for storage. You'll be glad you did.