Something I often hear other real estate brokers say about showing buyers homes: "When I hear the buyer talk about how the furniture is going to fit, I know they're hooked on the house."
This might well be true of some buyers, but my personal experience differs.
When my husband and I were house-hunting, we discussed furniture placement at least briefly in most every house we visited unless we'd already run across something else in or on the property that was a deal-breaker. We were getting a big old L-shaped leather sectional couch from my Mom (Thanks, Mom!) when she moved (we moved back to the area within 1.5 miles, and Mom moved out of state; sheesh, we swore we shower regularly and promised we wouldn't stalk you!).
Some of the houses we visited wouldn't suit the couch, most others did. Whether or not this particular couch would fit wasn't a deal-breaker in and of itself , but it was certainly on our minds as we walked through. We thought about it, we talked about it amongst ourselves, and we wondered about it aloud. All that meant nothing at all in terms of whether or not we were head over heels about the house itself.
My thought: Unless you are planning to purchase all new furniture to put into your new home, knowing whether or not your current furniture fits can be a big deal. Chances are you want to know that even if you aren't in love with the property, just in case it turns out to be your backup option. Will the couch fit? The oversized bed? That wonderful armoire Grandma left you?
I encourage you to take the time to measure rooms and consider layouts. To aid in the process as you tour homes, I've put together an article with additional information.