Hiring a personal trainer used to seem an expense of time and money reserved for the rich and famous.

But today, with so much emphasis on healthful living and an array of training options, even everyday workout warriors are going the professional route.

Finding a trainer has never been easier. Most gyms have trainers on staff, as do many companies as part of their employee wellness programs. There are also private practice fitness experts who will come to your home or gym to coach you. And apps such as "Find Your Trainer" serve as matchmakers between you and local trainers.

To get the most out of your investment, do some legwork before you get started. Here are some tips, from Lisa Ferguson-Stegall, an exercise physiologist and assistant professor of biology at Hamline University, on how to find the right trainer for you:

Ask about their credentials. Qualifications vary widely among personal trainers, so ask what certifications a trainer has and whether they've stayed current with their training. The four main national accreditation organizations are: American College of Sports Medicine; National Strength and Conditioning Association; American Council on Exercise, and National Academy of Sports Medicine. "If you see someone with one of these, you know that person has had proper training," Ferguson-Stegall said, noting that all of these groups require at least a bachelor's degree in exercise science.

Find out about coaching style. "The key word in personal trainer is the 'person' part," Ferguson-Stegall said. Determining whether a trainer's personality meshes with your own is crucial. Some trainers take a stern approach while others use encouragement to affirm and motivate clients. "Personally, I wouldn't want someone screaming in my face like boot camp, but for some people, that motivates them," she said.

Be clear about your goals. Do you want to lose weight? Are you looking for someone to help you train for your first marathon? Identifying your goals will help you find a trainer with the expertise you need to accomplish them. The high school athlete looking for help training for a race has different needs than a 60-year-old who has not been exercising regularly and wants to start working out for better health, Ferguson-Stegall said.

Keep costs down. Generally, it will cost you less for personal training sessions at a gym where you already have a membership. For some people, just meeting with a trainer a few times to talk about their goals and get on the right track is enough. That's a nice compromise that allows you to receive technical help in making a good fitness plan without having to invest in more training sessions than you need, Ferguson-Stegall said.