This study addressed the question of how two sides of being constantly connected to work (i.e., availability and interruptions) affect work performance. Applying Self-Determination Theory's (SDT) three basic human needs to the communication realm, we examine how being available for others versus being interrupted by others affects feelings of communication control (autonomy), communication effectiveness (competence), and social support given to and received from coworkers (relatedness). In turn, we examine how availability and interruptions relate to work performance through those three mechanisms. The results of Study 1, a five-day diary study among 317 employees (n = 1135 days) show that daily availability is positively related to work performance through higher levels of communication effectiveness. Daily interruptions are directly negatively related to work performance. Whereas daily availability is positively related to experienced communication control, daily interruptions undermine feelings of control. Study 2, a five-day diary study among 72 employees (n = 324 days) replicates those findings. The two studies further reveal that on days on which employees are more available they provide more emotional support, and they receive more instrumental support from coworkers. On days with more interruptions, employees provide more instrumental support to colleagues. The findings advance theory by applying insights from SDT to the organizational communication literature, developing and testing a model that explains why constant connectivity has pros and cons for work performance.