3/4 or 1 inch service

Hi! I'm going to be getting a the water service to my 80 year old house replaced soon and I'm wondering what size service I should consider. The city (Toronto) has a free replacement service (for the portion up to the property line) which will install 3/4 inch service. For an extra $200, they will install a 1 inch service.

I have a 2 storey semi-detached house, with two full bathrooms (one on main floor, one on second floor), laundry in the basement. We are planning, in the next couple of years, to build an addition on the top of the house (third floor) which will be a new master bedroom, and an ensuite bathroom (with shower and/or tub).

I have been given conflicting info from some contractors about whether 3/4 in sufficient for my future plans or I should spring for the 1 inch service (the extra $200 is only for the city portion, the portion on my property would also be more expensive if I opted for the 1 inch over 3/4 inch, so all in all it would likely be about $500-$1000 more, or so I'm guessing).

Looking for any expert (unbiased) advice. Thanks!

I would lean toward the 1" because of the future uses planned. The 3/4" would possibly get you by, but I fear in the future you may regret not going larger. You didn't mention how far you have to pipe, so it's pretty hard to determine what a reasonable price would be. Any added costs for the 1" should only reflect the difference in pipe and fittings. The difference in time to solder a 1" fitting over a 3/4" fitting would be virturally nil and the trenching is the same. Retail store prices would be higher than the city and your contractors would pay, but a comparison of 3/4" and 1" pipe at a retail outlet would give you an idea of how much extra you would have to pay for the 1".