If it's a machined part, then you need to dimension/Tol everything so the guys on the floor know how to machine the part
If it's a molded part, some dim can be avoid
The tolerance is very much based on the fitting between parts in the assembly
When you add GDT to your dwg, then you need to add MMC, LMC depends on how to use material for your parts
I think you are in the wrong place to get a definitive answer relative to GD&T.
May be worth taking some classes...
I agree. GD&T classes are a must.
On a side note, most drawings have a general note like: All untoleranced dimensions are +/-.005 or something like that.
There is not one answer for this.
It depends on so many factors, for instance:
Is this to be 3D printed from the model or machined, molded ...
What standards does your company use?
What is the purchasing companies requirement for tolerance?
What are the specifications of any mating parts?
There are just too many things that would determine this.
My company doesn't use formal GD&T We just specify tolerances and make notes where things are critical.
I have worked in places that did use "Basic" GD&T - some things defined in detail, others not.
You should know at least basic GD&T but most companies don't require every designer/drafter to be an expert.
GD&T are use for parts that are mating together it's also used for reducing cost of manufacturing the tighter the tolerance the cost become higher. As mentioned above it depends on the kind of parts to be manufactured because in reality it is very hard to manufacture a perfect parts. Some company has a GD&T Specialist so that designer and engineer will concentrate in there worked.