I have started using the titanium replacement blades because they seem to last longer than the regular blades. They are a tad higher in price initially but since I don't buy them as often, I save money. Shipping is great and the prices more than reasonable.
Fit my Fiskars trimmer exactly. They are sharp and perfect for trimming photos.
I've been using these replacement blades for over a year now. When I started using them in 2012, they worked well and took weeks to dull. Now, they dull within a couple of days' worth of use. I don't think I've changed the number of times I've been using them in that timeframe. These "titanium" blades don't seem to last longer than the "regular" blades, either.