There are also legal implications for staff working too many hours, as they may risk running afoul of the EU Working Time Directive; in the UK this typically means that workers may notwork more than an average of 48 hours per week. An efficient T&A System should warn in advance if this is likely to happen in the near future.
For many staff, who may wish to earn extra money for personal reasons, this may merely be a question of them contracting out of the Working Time Directive, which should be noted accordingly in the T&A System. If they do not wish to opt out, then the system should ensure that are not allowed to do overtime which would cause them to exceed the limit on the average number of hours worked per week.
It is important to note that those who work night shifts are generally not allowed to opt out of the Working Time Directive requirements because it is a safety issue, particularly if they are operating equipment. There are also special rules concerning young staff, which should be tracked automatically by the system.