Hello Parag
In addition to test between charts being public and not, there are other options. While making the charts private is one, the downside is that everyone will have to create thier own Analytic and Dashboard.
If that is not desired, you can test with the visibility filters, as they will be respected in the Analytics as well.
For example planer A can see all data for customer 123 and planner B can see all data for customer 456. If you leave analytics and dashboards on public, you can create one analytic without any filters and assign it to both, planner A and B. They would then not see each others data as the visibility filter would be respected.
Another advantage of keeping analytics public is that if planner A created an anaylitc, planner B can use it (open, adjust and save under his own).
You have to look at what your requirements are.
Cheers,
Jens