the thing about upping the service is you run into other issues. i KNOW that inspectors in my area will try to, and usually will, force you to bring other items up to current code. a good friend had a bad panel replaced, the EC pulled a permit for it, and the inspector made them go back and GFCI the outdoor/bath outlets before he would sign off. heck nothing was touched on those other than disconnecting fromthe old panel and pluggin most of the same breakers back in the new one. but he insisted tha tbecause the circuit was "touched" it had to come up to current code. With 100 amp service, you are limited to about 5 circuits total. common misconception, totally wrong, but common. at my house i have all my 240v breakers in the outside panel. there are 2 100A breakers, 2 60 amp breakers, 4 50A breakers, 2 30A breakers. that is a total of 580A! do i have 600A service, NO. i DO have 300A service though( i posted before that it was 400, but a friend who is a sparky corrected me). 1 of the 100A breakers feeds my indoor panel which feeds all the 120v circuits inteh house. this is a 24 slot panel with 22 20A breakers in it(the whole house is wired with 12/2 even the lights). that is 440A worth of breakers! you can have 20000A worth of breakers on a 100A service. it is not the size of the breaker, it is the size of the actual LOAD that determines service size.

The city told me that there is now an ordinance to bury the lines 200 amps and over. Our stove, hot water heater and furnace are gas. The clothes dryer is ready to be replaced and it will be gas. We don't need air conditioning in this area. If nothing else would upgrading to 100 amps be a good improvement to make for the future for other home improvements? Would the 100 amp service also add value to the house or would it just be an expensive upgrade to go over the 60 amps? The electrician says going up to 100 amps is a necessary upgrade.

Have you ever tripped your main breaker? Rather than us guessing, why don't you take an inventory of the major appliances, along with their wattage and voltage rating (120/240). The wattage will be on a plate. If you can't find it or it's not easily accessible, Google it. Major appliances would be those things that use electricity to heat or run a large motor. Stove, water heaters, pool motors, spas, clothes dryers, electric heaters, air conditioners etc. are all in this category. Doing the math would take a few hours and is certainly cheaper than a new service. A better way to do this is just to hire someone with an amp-clamp to measure the current on each leg of the main with a representative number of appliances working at the same time. A more valid test would be to record use over a day or two with a meter that records and charts the data (fluke 289, for example. Just getting the peaks will be deceptive because of motor start-ups). You want to be less than 80% of your breaker rating. If you are close, you should consider ways of reducing energy use - it could be a lot cheaper than a new panel. If you have a lot of incandescent lights, replace the bulbs with energy saving florescent bulbs, for example. Consider high efficiency AC units too. You might even consider changing your water heaters to gas (perhaps gas tankless), since it's available.

I mean no offense by this comment, but it strikes me that you really need more than the answer to this question. The entirety of the current service needs to be evaluated by a professional before attempting a DIY upgrade. This is especially true because it is a multiple unit dwelling. My guess -- and this is no more than guesswork -- is that two "very old panels", each of which are on 40-amp breakers, are very likely 60-amp panels. If that is the case, they cannot safely handle 100 amps, much less 200.