Do I need to worry about Min/Max footprint length values in datasheets
It may be a bit confusing that there's a difference between who's job it is to guarantee that the manufactured sizes are within spec:


The component manufacturer has to make sure that the actual part complies to the package drawing and lies within the tolerances.
You, being the one who is responsible for the PCB, are the one who has to make sure that the actual, real PCB is within the specification of the recommended solder pad layout. The tolerances are there to help you: As with anything real, you won't be able to manufacture a board with 1.8 mm and +/- zero tolerance, but you can make a board with 1.8 +/- 0.1 mm.


What the datasheet tells you is that any part within worst case tolerances will be good on any real board within worst case tolerances. If they just gave you nominal values, you would be facing the impossible task of making a real board with theoretical, ideal tolerances. Thus, again, the tolerances are there to help you, they're not created to have you worry: Specify the nominal (typ.) values when creating your decals, and relax in the comfort of +/- 0.1 mm when having the actual board made.

Sometimes, you will find different drawings between various manufacturers for a part that's practically derived from the same standard case outline. If you wish to have decals that are good for parts sourced from multiple companies, you can attack this problem from two sides:


Start with the available drawings and specifications: It helps a great deal to compare similar drawings from a number of different manufacturers; say, for example, 0805 capacitors from AVX, murata, Kemet and whatnot, or MSOP-8 ICs from TI, Fairchild, Linear and whoever. Then, try to create footprints that agree with any of these manufacturers' standards and min/max tolerances. If you have access to sources that are not specific to one single manufacturer, like IPC (Association Connecting Electronics Industries) or JEDEC, and you can bring them to agree with what you've figured out, even better.
Start with information based on practical experience: Ask your place-and-solder shop what works best for their soldering processes (reflow?, wave?) and machines (temperature profile?, type of solder?). They will likely know that pads with a slightly larger or smaller dimension in one or another orientation help them to avoid unwanted things like tombstoning of chip capacitors or resistors.


Ideally, all the information you can gather will not contradict and you end up having Your Pefect DecalsTM.

Related, but not a duplicate: The &quot;right&quot; 0805 footprint land pattern