Watch maker jargin is always very vague... if you haven't noticed yet. While I don't have all the answers, I can give you a few ideas to point you in the right direction to spend your money wisely.
What is a Complete Maintenance Service?
1. Dismantling, cleaning, assembly, oiling and timing of the movement.
Basically they tear down the movement and remove all jewels. They clean the movement using a special machine that looks like a tri-blender-inside-a-box. They place all the parts (or full movement) inside a screened basket separating the parts inside their own section and then a screened cover goes on. The machine will clean, rinse and dry the parts automatically.
2. Replace or repair parts that are worn or damaged.
Once the parts are cleaned and dried, the watchmaker will inspect the parts, fix/replace the parts that don't make the "grade" and assemble the movement while oiling it.
Many watchmakers will automatically insist the hands are replaced. Hands are friction fit so reusing them could cause them to hall off in the future. once the hands fall off, the watchmaker has to clean the movement again costing them time and money. This goes for dials (dial feet could be old and tired and the push-pieces for chronographs/calendars)
It is important to note that not all movement parts can be repaired or replaced. Some older watches more than 20 years old may not have parts available and therefore parts need to be made or repaired by a "Master Retorator". Many repair shops do not "restore" parts because of the great deal of time, money and energy goes into making parts. (restoration typically makes one part at a time, therefore the parts are made by hand using hand adjusted tools.)
What is a Complete Maintenance Service?
1. Dismantling, cleaning, assembly, oiling and timing of the movement. Basically they tear down the movement and remove all jewels. They clean the movement using a special machine that looks like a tri-blender-inside-a-box. They place all the parts (or full movement) inside a screened basket separating the parts inside their own section and then a screened cover goes on. The machine will clean, rinse and dry the parts automatically.
2. Replace or repair parts that are worn or damaged.
Once the parts are cleaned and dried, the watchmaker will inspect the parts, fix/replace the parts that don't make the "grade" and assemble the movement while oiling it.
Many watchmakers will automatically insist the hands are replaced. Hands are friction fit so reusing them could cause them to hall off in the future. once the hands fall off, the watchmaker has to clean the movement again costing them time and money. This goes for dials (dial feet could be old and tired and the push-pieces for chronographs/calendars)
It is important to note that not all movement parts can be repaired or replaced. Some older watches more than 20 years old may not have parts available and therefore parts need to be made or repaired by a "Master Retorator". Many repair shops do not "restore" parts because of the great deal of time, money and energy goes into making parts. (restoration typically makes one part at a time, therefore the parts are made by hand using hand adjusted tools.)
People naturally assume Abraham-Louis Breguet in 1795 (patented in 1801) was the first person to create a Tourbillon small enough to fit in a wristwatch, but you would be wrong. He invented the Tourbillon for pocket watches and clocks. It wasn't until 1947 when OMEGA created it. The OMEGA caliber 30I was the first Tourbillon wristwatch caliber in the world coming in at 30mm wide. Only twelve of these movements were made for the observatory timing trials in Geneva, and they were known as the OMEGA Observatory Tourbillons. 
Do you have an OMEGA and need some guidence on working it? Can't find the manual? Here is the answer: