Been a while since I shared any #mac#tip. So here's one that's pretty useful if you regularly had to deal with PDF files that are too large to send through emails. Long story short, create a new Quartz filter using ColorSync that would reduce the DPI and compress the pages using JPEG @ 80+% quality. Then move from ~/Library/Filters to /Library/PDF Services. Then use Preview app's Export option and set it to export with the Quartz filter you've created. The longer detailed step-by-step screenshot version is here on my blogpost: How to compress PDF for free on your Mac