To prevent circuits from tripping how do you determine if you need to upgrade to a 200 amp service or keep 100 amp and add some circuits?
Upgrading your service will not keep individual circuits from tripping.
An overloaded circuit on a 400-amp service will still trip.
Large individual loads require their own circuit.
Large circuits with multiple outlets and numerous simultaneous loads should be broken up into multiple circuits as suit the loads.
The only time it is necessary to increase a service from 100 amps to 200 amps is when the combined loads dictate the necessity.
A 100-amp service is usually adequate for a three or four bedroom home with electric hot water, electric stove and electric dryer.
A 200-amp service would be necessary if total electric heat is contemplated. <><><>
As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
If you do this work yourself, always turn off the power
at the breaker box/fuse panel BEFORE you attempt to do any work AND
always use an electrician's test meter having metal-tipped probes
(not a simple proximity voltage indicator)
to insure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.