Should Shin guards be covering the knees

I am new to sparring and am in the market to buy new shin guards.

I am wondering if the shin guards should be covering my knees too. Largely to protect my sparring partners shins.

One of my sparring partners once blocked my body kick with his knee and even with a guard on it did hurt me quite a bit. I am trying to be considerate.

Will such a guard become too clumsy?

What are your thoughts?