Ex pen: yes or no?

[Bridget and Lupin]

We have 2 crates...wire one in the livingroom and a soft one in our bedroom, but I'm wondering if we should get an ex pen in case we need to corral the pup while we were home.  Are they redundant or essential?  Opinions please!  I was initially thinking I'd have him/her leashed to me in the house, but everyone tells me that will drive me nuts. 

Thanks in advance!

[Kyoko]

I have a crate and an octagon shaped baby gate. This can be made into a pen, or stretched out to section out the room, can be used in a various way. I love this gate and use it as a pen for the puppy ( 6 months old ) now when he cannot be supervised. ( Because he chews things he should not.)