Minimum # of days that one must be in the UK to extend visa?

I'm in the UK on a 3-year tier 2 visa. If my company wants to extend my visa by an additional year or two past its current end date, I assume they apply for a new CoS, and if they are successful I would then apply to extend my visa (correct me if I am wrong).

My question is, is there a certain number of days that I should NOT spend outside of the UK? I know that people on 5-year visas who think that they might seek ILR are advised to ensure that the number of days that they are outside of the UK does not exceed 180 days in total for the 5 year period. Is there similar guidance for people on 3-year visas who think that they might seek a visa extension?

Any assistance much appreciated.
-G

It is 180 days per 12 month cycle for ILR. NOT 180 in the total 5 years.

I am not aware of the absence limits you are asking about. Have you looked through the Tier 2 policy?

Absences from UK come into play only when applying for settlement (if one is eligible to apply for it, that is) ..... not at all relevant for extension(s).