Adina gave a solid answer- however reading between the lines brings about a question and answer that was not posed, but extremely relevant. Inflation is alive and well in select areas- many of which will directly impact your maintenance. In the last few years energy costs have skyrocketed. Water rates and Property taxes have too. These 3 factors alone could easily send your maintenance costs up 20-30% if your building didn't account for these increases in the last few years. Want to keep your increases lower, then Conserve energy (keep the heat lower), minimize your use of water, and convince the other shareholders to do the same. There may be other ways for the board to cut costs too- but it's not easy. As Adina recommended- check the expense report- perhaps your building has had other expenses that justified this large increase. I doubt the members of the board (who would be your neighbors) wanted to pay this large of an increase either.