If you’ve been in business for any length of time, you’ve had at least one bad client. While some entrepreneurs seem to be born with an invisible force field that repels bad clients, others attract them like a picnic lunch draws ravenous ants.

If you’re in the latter category, there’s hope. You too can learn to spot bad clients before they become a drain on your time and on your business.

There are many different types of bad clients, typified by certain undesirable traits. Here are six of them.

1. Time wasters.

Time is money, and the financial success of your business depends on using your time efficiently. Clients who tell you they want one thing and then change their minds time and time again after you’ve provided exactly what they said they wanted waste your time and make you less productive. There are only a limited number of hours in a day, so don’t squander them on bad clients who continually disrupt your workflow.

Related: Don't Let Your Business Be Held Hostage by a Nightmare Client

2. Energy zappers

Along with time, energy is an entrepreneur’s most valuable and salable commodity. Uncommunicative, uncooperative or just plain obnoxious clients drain your energy. Their tactics can range from persistent passive-aggressiveness to outright verbal abuse. Worst of all, their negativity is contagious. Try to drop these vitality-vampires like a bad habit before you get sucked in.

3. Fee hagglers.

Clients who pester you to lower your fees don’t truly value what you provide, and most likely never will. However, there are exceptions. Clients who are trying to get their business off the ground may have limited funds, or may be working for a cause that you passionately support. Just be aware of what really matters to you, and set clear boundaries when deciding whether to accept “charity” cases.

4. Commitment phobic.

Some people like to “shop around” and consider all their options before they choose how to spend their money. There's certainly nothing wrong with that, as long as their actions can signify that they’re serious about finding the right fit for their particular needs. Beware. Their indecisiveness could be a red flag warning they may well repeat that pattern once you start working together.

Related: Why You Should Fire Your Worst Client

5. Criticizers and complainers.

Some customers are never satisfied, no matter what you do to please them. When clients provide negative feedback about your pitch or the work you’ve done, it’s important to determine its validity and make improvements as indicated. But some people make it a habit to continually criticize and complain about everything because nothing is ever good enough for them. It’s good sense to avoid these bad clients whenever possible.

6. Late payers.

You have a business to run, which requires steady cash-flow, so clients who don’t pay invoices on time disrupt your financial viability. But perhaps more importantly, people who constantly delay payment don’t sufficiently appreciate the value you bring to their business. When clients fail to meet payment deadlines, stand your ground. If you’ve met your obligations, they need to meet theirs. Those who repeatedly don’t pay up promptly are less-than-ideal clients.

To run a successful business, you can't spend your time nursing bad clients. Avoid them (or fire them) and you will have more room to focus on clients who are a joy to work with and appreciate you.