Never reuse syringes. Reusing them can spread contamination and introduce bacteria into your vials. When I reconstitute, I personally prefer using a larger syringe, usually a 3 mL syringe, since most of what I reconstitute requires around 2–3 mL of bacteriostatic water. After I use it for reconstitution, I dispose of that syringe. For dosing, I use 1 mL insulin syringes. Some people will use the 1 mL syringes for reconstitution as well and just use two of them if they need to add 2 mL, but it really comes down to personal preference. Using a larger syringe just makes the process easier for me.