In meditation, we are taking a break from the outward, physical experience of life in favor of existing more in the inward realm of thoughts and feelings.
Therefore, it matters less what style you do or how well you do it, just so long as you are taking a break from the outward, physical experience of life, you are meditating and likely getting some of the health benefits.
Maybe this is just closing your eyes while you sit on the subway with your earbuds in listening to whatever brings you peace. Maybe it is doing a few repetitions of slow breaths with your eyes closed in between staring at the computer screen for hours. Or maybe you are sitting on a pillow in a mountaintop ashram in Tibet astral projecting your spirit body to alternate dimensions. In all these cases you giving your body and mind the much needed break from the stressful material world. Not that the outward, material world is inherently bad, but if that’s all you are ever getting you are putting yourself out of balance.
This balancing act between extremes is present in every important place you look. For example, in exercise, if you are constantly putting strain on your muscles, they never get a chance to rest and repair. Thus, you won’t actually get bigger, stronger muscles and your hormone system will be out of balance. However, if you get a balance of both exercise and rest, everything works better and the exercise is healthy.