Final answer:
Incumbents benefit from franking privileges, which is the ability to send mail to constituents for free. This perk, combined with high name recognition and existing campaign resources, significantly contributes to the incumbency advantage in elections.
Step-by-step explanation:
Incumbents in public office enjoy a notable benefit known as franking privileges. These privileges allow them to send mail to constituents without incurring postal costs, which helps them maintain visibility and a connection with voters without spending campaign funds. Despite being advantageous, franking is regulated; for instance, incumbents cannot use this free mailing service close to an election—a senator is restricted within sixty days and a House member within ninety days prior to an election day.
Building upon a pre-established campaign organization and having more financial resources than most challengers constitutes a substantial part of the incumbency advantage. Additionally, incumbents are able to leverage state power, such as conducting constituent casework which, when publicized, can significantly bolster voter support. A key aspect of the incumbent advantage is the higher level of name recognition an incumbent typically holds, which is enhanced by self-advertising and the resulting familiarity among voters. This dynamic has led to a high reelection rate for incumbents in both congressional and local elections, often referred to as the incumbency effect.