Lets backup here a bit... Do you have an antistatic mat?
If you do, you can attach it to it and as long as you don't create a static charge by getting up you'll be fine. Make sure to place all of the tools and other gear on the mat so they are all at the same static charge.
Think of it this way: In a helicopter in the air there is no ground point so the metal frame of the copter is the reference so all of the devices within it at at the same charge. Now as the copters blades are moving through the air they collect a static charge (5,000 to 20,000 volts) so the frame has this charge!
Now think what happens when the copter is trying to save someone in the ocean if he drops a line to the person (insulated) to grab as soon as the person is raised to the open door the person reaching for them would give them (and them selves) a good zap! Or if the line was conductive the person reaching for the line in the raft would get the hit alone! Still not good! This is why the pilot always dips the cable into the ocean just before getting it to the person to equalize the charge.
So what does this have to do with your antistatic wrist strap? Quite a lot! As the same holds true here. All you need to do is think like to copter pilot. Place every thing on the conductive mat and then use it as reference. As long as you don't move your set. If you must get up, touch the mat first and wait a good 15 sec's before continuing.
The risk of ESD is dependent on how much static electricity is in your environment. In the winter months, as well as in the arid enviroments static is a big problem. So depending on where you are and when you are planning on working on your phone the risk of ESD damage fluctuates.