Personally, I am not a very eye-contact heavy person and when sparring I accordingly have a defocussed look which goes through my partner's midsection and with which I try to take everything in at the same time.
Would you rather generally recommend 1) this defocussed look or 2) looking your partner/opponent in the eye and why? Personally, I would still need to force myself to do the latter and should be doing it to experience the differences.
Furthermore, when do you recommend to deviate from either your 1) or 2) standard? For instance when looking at incoming attacks for optimal blocks? Do you switch from defocussed to eyes or vice versa when sparring/fighting?