Some drugs are difficult to take, because they must be taken at a specific time or interval; sometimes, several drugs must be taken together. This is seen as a major obstacle to compliance. Other factors that may adversely influence compliance are that many patients do not understand the benefits of being treated, or they see side-effects that they were not told about, the drugs costing a lot of money, poor communication or lack of trust between the patient and their health-care provider. Efforts to improve compliance have been aimed at simplifying drug packaging, providing effective medication reminders, improving patient education, and limiting the number of medications prescribed at the same time.