Not sure about the magnetised screwdrivers, not the best tool to use around electronics. The other thing that we should consider is ESD - Electrostatic Discharge - you can quite easily kill an electronic circuit or chip with the static electricity generated by your body, good idea to earth yourself and the watch or module to the same point. Stores like Maplins (UK) or Radio Shack (US) can sell you ESD mats with a wrist strap that connects by curly cord so that anything on the mat is same potential as yourself.
When I worked in advertising photography and we were photographing carpets we had to earth ourselves before accepting a cup of coffee as the potential built up walking on the artificial fibre was enough to cause a shock between the coffee donor and acceptee with hilarious coffee stain on carpet consequences.
We earthed ourselves on a metal pillar of the studio - slowly offering the knuckle of a finger toward it. You could get a spark of about an inch - 2.5cm to you youngsters out there

You can easily charge yourself to around 40,000 volts which is enough to cause problems with chips and ICs.