I lay mine flat.

All my mats are laid flat -- rulers are everywhere :lol:

DH put a shelf up that runs the length of my sewing room. I have all my quilting books on it and I stack my mats and rulers on the end.

My big mat lies flat the the cutting table. My smaller mat fits perfectly on a drawer "shelf" in my sewing cabinet and my itty bitty trimming mat is in a drawer in my cabinet.
My rulers are in a letter holder type unit on my cutting table.
I do have a mega giant size mat standing behind my china cabinet in the dining room but have not used it in a couple years. If I decide someday to open my cutting table all the way up, it will fit on there.

rulers hang on a door between the sewing room and the laundry. clank. the matts lay flat in a blueprint cabinet drawer (david is a retired architect).

I keep mine flat on my sewing table......or if I'm using that they go on my computer desk. I don't have room to hang them or I would.

My mats are laying flat....small ones side by side under the large one on cutting table. My rulers are in wooden slotted rack and large ones in dinner plate divider holder I got at local thrift store for 50 cents....works great for those big square ones and circle cutting ones, etc.

Mats hang on a skirt hanger. Rulers hang on the pegboard.

I hang my mats on skirt hangers on the back of the door. I have a couple of rulers with holes which I hang on "s" hooks.

This is what I use for my rulers

It's made of pet screen pieces that have been edged with bias tape and then sew to one huge piece of pet screen. The top has been folded over to make a casing for a wooden rod.