If you have a specific fitness goal, consider following a specific program created for that goal. If you want to run a 5K race, for example, following a 6-week 5K training program will prepare your body better than simply running a few times a week.
This seems intuitive, but it’s good to understand why: Doing a similar workout over time makes your body adapt to that challenge by getting fitter and stronger. This is exactly what you want when you have a specific goal, like a heavier deadlift or a faster race time. If you switch up your workout too often, though, you’re not forcing your body to adapt in a specific way.