Re: How do you know how much work you need?
Just a guess but I'll bet you have an old house with a 60 amp service and old wiring that has been kludged and added to.
I would suggest you get several estimates on upgrading the service and rewiring. You can have the new wiring, new panel and new meter base installed while maintain the existing wiring. Once it is done the new drop can be added and connected to the meter base so you will be without electricity for a very short time. Then the old wiring and fuse panel can be removed or decommissioned.
Be sure you live your life, because you are a long time dead.-Scottish Proverb