It is up to the traveller to decide whether expenses should be compensated by hourly and daily allowances or by reimbursement when the trip includes an overnight stay and lasts more than 24 hours.
If the trip does not include overnight accommodation or lasts less than 24 hours, expenses are always reimbursed. The duration is usually calculated from the workplace, but can be calculated from your place of residence if you live closer to the destination and are travelling directly from home.