Re: ritual casting

Combat encounters in my game rarely last a full 5 rounds*. Per this rule, rituals would still not be used in combat unless I made an encounter that specifically required them. Would you suggest lowering the minimum cast time of rituals for my group? Perhaps to the average number of rounds (It hovers in the 3 to 4 range) of combat -1?

Or is the intent to keep in combat use very rare?