Sound retirement planning depends on your ability to accurately project your spending after your career comes to an end. However, even the best-laid plans can fall apart if they leave the door open for unpleasant financial surprises — one big one, in particular. The following analysis outlines how much the average retiree spends every month and reveals a potentially massive, but often underestimated expense that can sneak up on seniors, forcing them to revise their spending plans, restrict their budgets a ...