I have the screw loosening problem also!Can be a real pain.
Might be time to think about a new cutter!

I love my fiskers.. have had it 7 years.. never had a problem.. I thought of changing but WHY... it isn't acting up and I could buy fabric instead of a cutter.

I have a Martelli cutter and like it much more than Olfa or Fiskars, I have tried them all.

I never heard of a Martelli so I googled it. I sure like the looks of it. Very sensible design. I wonder, do they use the same 45 blades? The sharpener isn't cheap but it pays in the long run.

I have a Fiskars cutter. It goes through blades pretty fast but I'm pretty sure that is because I cut like a drunk and run into my ruler! The screw has loosened a few times, but it's never been a problem.

I only have Fiskars, so I cannot compare them with anything else. However, I like mine a lot. The blades seem to do well in it.

I have a rotary in every brand. My favorite is the Martelli. I keep all of them in a drawer under the cutting table and which ever one I pick up is the one I use. Recently I tried the "turn your blade over and add a drop of oil". It worked great. Made the blade last twice as long.

I have the Fiskars and like the feel of the handle in my hand and it's really easy to use. My screw does come undone, but it doesn't bother me.

At the quilt show I bought my Martelli cutter and it comes with 5 blades. according to them those 5 blades should last you several years.......

the blades DO last a long time, but if you are not careful on your cutting they do bend, which makes a kink. Martelli blades are NOT interchangeable with the others.

I go through about 2 blades a year.