We’re all too busy, spending our days in back-to-back meetings and our nights feverishly responding to emails. (Adam Grant, a famously responsive Wharton professor, told me that on an “average day” he’ll spend 3-4 hours answering messages.) That’s why people who waste our time have become the scourge of modern business life, hampering our productivity and annoying us in the process.

Sometimes it’s hard to escape, especially when the time-waster is your boss (one friend recalls a supervisor who “called meetings just to tell long, rambling stories about her college years” and would “chastise anyone who tried to leave and actually perform work”). But in many other situations, you can take steps to regain control of your time and your schedule. Here’s how.

State your preferred method of communication. For years, millennials have famously eschewed phone calls — but almost everyone has a communication preference of some sort. Regina Walton, a social media and community manager, told me that she, too, hates talking on the phone, a habit she developed after years of living abroad; email is almost always better for her, as “I can respond when I have time and usually am very fast to reply.” You can often limit aggravation (and harassment via multiple channels) by proactively informing colleagues about the best way to reach you, whether it’s via phone calls, texts, emails, or even tweets.

Require an agenda for meetings. Pointless or rambling meetings account for a disproportionate share of workplace time leakage. Here’s a solution: insist on seeing an agenda before you commit to attending any meeting, “to ensure I can contribute fully.” You can model the practice by writing an agenda for any meetings you chair, and offering to share the template with others. In fact, you could push to establish company norms that include best practices such as eliminating generic “updates” (which can usually be emailed in advance) and clearly indicating the decisions that need to be made as a result of the meeting. “Discuss expansion strategy” would be a murky and perhaps unproductive agenda item; “Decide whether to open a Tampa office” can guide the conversation much more clearly.

Police guest lists. Meetings are also dangerous when their list of invitees has been wantonly constructed, filled with irrelevant people and lacking decisionmakers with the authority to get things moving. If you’ve been invited, ask two critical questions. First, do I need to be there? Looking at the agenda (which you’ve insisted they provide), you can gauge whether your input would be valuable or if you can just find out details afterwards. Second, will the (other) right people be there? If you’re theoretically deciding on the Tampa expansion strategy and the executive in charge of Southeast operations isn’t in the room, it’s likely you’ll have to repeat the whole process again for her benefit. Make sure you understand who the real decisionmakers are, and don’t waste your time (or other people’s) until they can be present and participate.

Force others to prepare. We all hope and expect that others will prepare for meetings with us. Surprisingly often, they don’t. Even when they’re requesting the meeting, they may have done very little research and waste our time with extremely basic questions they could have Googled. Instead, we need to force others to prepare in advance. “Force” is a harsh word, and that’s intentional ­— because it’s not burdensome for people who would have prepared anyway, yet it effectively weeds out the uncommitted. Debbie Horovitch, a specialist in Google+ Hangouts, has long offered complimentary initial strategy sessions, but realized that some people were taking advantage with irrelevant discussions.

She’s adopted a new policy: “Everyone who wants a call/chat with me must fill in an application” with specific questions about what will be discussed. “Now that I’ve set my boundaries and expectations of the people I work with, it’s much easier to identify the time wasters.” Similarly, when people request informational interviews with me, I’ve begun sending them a document with links to articles I’ve written about their area of interest (becoming a consultant or speaker, reinventing their careers, etc.) and asking them to get back in touch after they’ve read them to see what questions they still have. Most never get back to me, which is just as well ­— I only want to speak with people who are interested and committed.

Will you face blow-back by toughening up and putting clear boundaries around your time? Inevitably. But you may also find that people start to respect you ­—and your time ­— a lot more. Most of us wish we could control our schedules better. If you’re willing to step up and argue for smarter policies (like requiring all meetings to have agendas), that benefits everyone. The key is to frame your advocacy not as purely self-interested (“I don’t have time for this nonsense”), but instead as a manifestation of your commitment to the company and your shared mission. “I want to make sure we’re all as productive as possible,” you could say, “and that’s why I think it’s important to make sure we’re respecting each other’s time.” In the end, that’s a hard message to resist.