Through the study of archaeological evidence from Pompeii we can learn that benefactions were not optional, but required of a duumvir, during time in office. There were different types of benefaction; from privately funding public buildings to putting on ludi. We can see from inscriptions that regulatory benefactions were in the form of ludi.
CIL X 854
Titus Atullius Celer, son of Gaius, duumvir, instead of games and lights, saw to the construction of a seating sector, by decree of the town councillors.
CIL X 857d
Marcus Cantrius Marcellus, son of Marcus, duumvir, instead of games and lights, saw to the construction of three seating sectors, by decree of the town councillors.
This shows us that on this occasion, the Ordo made the decision to allow the magistrates in office at the time to build seats in the amphitheater instead of paying for ‘games and lights’. This allows us to infer two things, that the necessity of benefactions was decided by the Ordo Decuriones and that the usual type of benefaction was paying for games and lights.
Although all officials were required to put on games (or equivalent if the Ordo deemed it necessary) some were evidently more generous than others, such as Aulus Clodius Flaccus and Gnaeus Alleius Nigidius Maius.
Apart from the ludi benefactions which were necessary, many councillors also used their own money to pay for building and restorations at their own expense. This would have heightened prominence in society and benefactions were also very important if one wished to move up political ranks, such as becoming quinquennial duumvir.
RESTORATION AFTER AD 62 EARTHQUAKE – CIL X 859
Gaius Cuspius Pansa, son of Gaius, the son, priest, duumvir with judicial powers.
CIL X 852
Gaius Quinctius Valgus, son of Gaius, and Marcus Porcius, son of Marcus, quinquennial duumvirs, for the honour of the colony (of Pompeii), saw to the construction of the amphitheatre at their own expense and gave the area to the colonists in perpetuity.
 Beard,2008: 198
See CIL X 1074d, CIL IV 1177 and CIL IV 7990