Newly built homes today usually have up to 200 AMP electrical service because we now have so many things we plug in that use a lot of power and need lots more circuits to operate our homes safely.
If you have central air conditioning, electric stove, electric water heater etc then 200 AMP electrical service would be best because it would prevent too much power draining your 100 AMP electrical circuit especially during start up such as a central air conditioner.
Central Air Conditioners use a lot of power when first starting so it can dim your lights and with 200 AMP service you shouldn't have that problem.
I upgraded from 100 AMP electrical service to 200 AMP electrical service and now my lights no longer dim when I'm using lots of electricity or when my central air conditioner comes on.
However I had to have the electric utility come out and install a bigger 200 AMP overhead wire to cope with the 200 AMP electrical service.
So if you can afford to then I would recommend upgrading to 200 AMP electrical service because the 200 AMP electrical service can also increase the value of your home if and when you decide to sell the house.