Don't be limited in your faith development by the limitations of the faith development of others.
The limitations of other people in their faith development should not have any bearing on you.
It is one thing to hear the experience of others and to learn from their mistakes. It is another thing to allow what they discovered as their personal limitations to become your personal limitations.
I would hope the reason they share their discoveries with you is so that you can surpass the boundaries they experienced. Sadly, most often naysayers are discouragers rather than encouragers.
If someone tells you an idea you have about growing in your faith will not work, they probably mean it will not or did not work for them.
Ironically, with a bit of inquiry you will typically find that the limitation was not with the idea, approach, or spiritual practice. Most often the limitation was with themselves. They gave up. They were not consistent.
The only way you will know if it will work for you is to try it.
One thing is for certain: If you allow the limitations of others to become your limitations, you will fail.