Do I need filters?

So, I was thinking that if my camera has white balance for:

Sunny, do I need an 81A?

Shade, do I need an 81B?

Cloudy, do I need an 81C?

How about high altitude: UV, 81A, CPL; K-5 has a UV on sensor so I guess I need to set WB to sunny and use a CPLO.

Any thoughts?

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-Richard
Pentax K-5 IIs, Sigma 17-50 f2.8 EX DC HSM, LX3, Pentax MX w/Pentax 40-80 & Soligor 80-200 f4.5 lenses, Lightroom 4.3, CS5