I use different threads. Coats and Clark double duty xp for most of my piecing. I also use Aurafil Egyptian thread it is very fine and does not lint up my machine only problem is that it is about $11. a spool of 1200 yards.
For blades I try to buy a 5 pak so I always have a spare (but I used to work at a quilt store and got a discount, not anymore..). I tried a sharpener but was never satisfied with the results.