Morning all - I have just had the lovely experience of my reply disappearing into thin air ... so here goes again
I have replaced the blade once in 8-9 years
There is no cutting mat
The plate used to hold the paper/card is transparent and has some subtle lines moulded into it that I also use for lining things up with.
So yes, you can see exactly where you are cutting!!!!
The plate also can be detached for cleaning the cutting channel - this usually does not get cluttered, but once in a while I take it off and give things a good sort out.
Love, love, love my cutter and would be lost without it!!