Ok, still being a newbie in the quilting world, I honestly do not know the answer. Is there an advantage to using a 60mm rotary cutter over using a 45mm? Does the 60mm cut through more layers of fabric more easily than the 45mm? I ask, because I am always trying to figure out better and less time consuming ways to cut. Thank you in advance. :)

I have both but use my 45 most of the time esp. since I found rotary blades at harbor freight for really cheap.I also don't cut more than 2 layers at a time because I have learned the hard way that one of the most important things you do it cut accurately!Nothing else matters if your cut is not spot on!

I was actually hoping that the 60mm might eliminate the little dips in the fold of the fabric when cutting more than 1 layer at a time. I will not use anything that does not have straight sides, therefore I end up with more fabric waste than I want.

I use the 60mm. It seems to be easier on my hand and wrist.

It won't eliminate the dips,I could be wrong and I am not sure why the dips occur in long pieces.I know if I cut 12 in. or less I don't get dips.

45mm blades are a lot cheaper than 60mm ones. 60mm are usually used when cutting many layers of fabrics. You get the dips when the folds are not straight--doesn't matter what size blades if the folds are not straight.

28 mm here, didn't care for the larger blades, to me less control, 8 layers no problem.
But that's what I started with, could be why.

great, thanks for the info. funny thing is i thought my folds were straight, but i guess that is what i get for thinking. lol so, i suppose my next question would be "how do i ensure the folds are straight". i spend the extra time to sooth, sooth, and resooth the layers and folds out. what is the trick? :)

I use both but yes, the larger ones are more expensive. I use my 60 a lot more I noticed.
It cuts so easily for me.

45mm is just a smaller blade to cut thru a few layers.. the 60mm will cut thru quite a few more layers than the 45mm. its all a matter of preference. Some think the 45 is easier to handler and others like the amount of fabric the 60mm will cut.. I have both and the 28mm for smaller cuttings that are more rounded.. Its a try it and see kinda deal..

I have one of each for sale if anyone is interested (listed in the classifieds..found them when I was cleaning my sewing room)

Quick Change Olfa 45mm & a 60mm