I've got a trick to make Mach 3s or any disposable blade last years. I've been using the same 8 pack of Mach 3 Turbos for about 5 years now. Before you go spend any money on fancy gear just try this for a month, you'll be blown away by how well it works. This has saved me hundreds, if not thousands of dollars over the years.
https://youtu.be/5ADaRIqy0Dc