walkable clipless pedal shoe to replace normal shoe? I have a touring bike which I use almost exclusively for commuting.  I am thinking about getting a clipless pedal with walkable shoes.  At the same time, my normal shoes which I wear when not cycling need to be replaced, and am thinking that to save money and avoid the need for carrying extra shoes back and forth, instead of buying two shoes I would like to buy a shoe that can both be used as a normal shoe as well as for cycling.

While I see that some clipless pedal shoes are "walkable" I don't see much if any data regarding wearing it as a normal shoe all the time.  Preferably I would like to get about the same amount of wear as a regular shoe out of it.   Just for normal everyday walking around the office, out to lunch, and that sort of thing.

Is there some specific model recommendations or something specific in terms of feature I can look for, or is using the same shoe for both things out of the question?  I think it will be required - and I'm definitely open to - using MTB shoes on a road bike (as I think the increased pedaling efficiency will outweigh the weight drawbacks considering my usage pattern), but if it can't be done I would prefer to not get clipless and just buy some inexpensive shoes and continue to use pedal clips.
I just leave a pair of shoes at the office and change shoes when I get there so I don't have to take them back and forth. It's amazing how much space shoes take up in a backpack/pannier. I think that even the "walkable" shoes aren't that comfortable to be in all day.  And any cycling shoes that you did want to walk around in all day would lose a lot of the advantages for having a dedicated cycling shoe, such as a stiff sole. My office shoes are just cheap ones I picked up at Walmart.  This also has the added advantage that if my cycling shoes get wet from the rain that I always have a dry pair to change in to.