Flying first Class is worth it on a number of occasions.

1.) If the flight duration is more than 4 Hours. For a flight less than than that duration it hardly matters where and how you are seated.

2.) If you are travelling with an infant or new born.

3.) If you are a elderly and flying alone.

4.)If your Company provides you the Tickets.

5.)If you have a lecture or seminar to attend just after landing and you need to be fresh.