I had to replace my trimmer a few months ago because I could no longer purchase replacement blades for it.
I bought
Fiskars 152490-1004 SureCut Deluxe Craft Paper Trimmer, 12 Inch and I like it very much.
The base is large enough that most of the time, I don't have to open the arm to cut what I need. I expect to be able to purchase replacement blades (which are the same for a number of Fiskars trimmers) for a long time.