Film Screen protection questions...for OM D E M5

Hello OMD EM 5 users...

1/ Would like to know if the film on screen does not decrease the sensibility of the touch screen?

2/What are the best brands...there are many films and some are probably not really good.

3/ are these film sticking well or do you have to replace them often ?

4/ If you have to remove the film , can you remove easily the glue from the screen  without damaging the screen?

5/ Are you many to protect the screen ... Do most people protect the screens ?

Thank you for your feed back.

Bernard