With the New Year’s resolutions to get fit and shed weight, fitness apps have become as ubiquitous as the ball drop at Times Square or the Rockefeller Christmas tree. But like those lofty resolutions, the use of fitness apps tends to fade relatively quickly. While they can be a great source of motivation to get moving, users must carefully choose the right app for their needs.

Fitness apps have become a booming business and developers continue to add new features to stand out from the competition. A few of the most important aspects to look for in a fitness app include:

Platforms available: A good workout app should be compatible with multiple mobile platforms, including iPhone, Android and desktop. Many also work with wearables such as smartwatches and fitness tracker bands. Some even have the option to stream classes to a TV. Equipment required: Some fitness apps offer high-energy, full-body workouts that require specialized equipment, such as free weights and kettlebells. Other apps, such as the 7-Minute Workout, feature simple workouts that can be done at home with minimal equipment.

Class length: Fitness apps that only offer long classes can cause some people to feel discouraged or overwhelmed when they don’t have the time to complete the whole class. Experts recommend that an app include a mix of shorter and longer workouts to make sure all users are motivated to move on their own terms.

Cost: While most fitness apps are free, some have a monthly or annual subscription fee. This is an important consideration because the price tag of an app should be consistent with the value it provides to the user. A good fitness app will help the user reach their personal goals, so the cost of an app should be in line with the results the user hopes to achieve.

A good fitness app should provide a range of classes for all fitness levels and ages, from beginner to advanced. For example, beginners may start with the Baseline Bootcamp series, which focuses on fundamental strength, while more experienced users can select the Superhero Series or the Alo in the Wild series, which explores iconic global destinations.

Some fitness apps have a gamification component to keep users engaged and motivated. For example, the Sworkit app lets you earn badges for completing certain workouts. Others have social components, such as letting users connect with other fitness fans and compete with them. fitness app