It depends hugely on the era you're talking about and what legion / where it was stationed / who their commander was.

I'd suggest trying to snag a copy of "De Re Militari" by Vegetius. http://www.digitalattic.org/home/war/vegetius/index.php#b119 if you want to just take a gander online. It's a short read and basically tries to explain in the context of the late empire, why the earlier empires army was so superior. It goes into great detail (it was actually used as a guide by subsequent militaries for hundreds of years) on the actual training regimen, discipline, how to keep troops healthy, and small unit tactics. It's great because it gives you very detailed info on what (at least they thought) the Roman army was like at it's height. You can also infer, by the fact that he's talking about a particular topic, that the Roman army of the late Empire was deficient in a particular area.

If you're comparing it to contemporary military experience it's actually pretty similar in terms of cleanliness (account for the much poorer understanding of hygiene / health 2000 years ago) / organizational standards. When I was reading it the first time it felt like sections of it were written by one of my drill sergeants in basic training.

​

Small sample to give you the gist:

" In former times the discipline was so strict that the tribunes or officers above mentioned not only caused the troops under their command to be exercised daily in their presence, but were themselves so perfect in their military exercises as to set them the example. Nothing does so much honor to the abilities or application of the tribune as the appearance and discipline of the soldiers, when their apparel is neat and clean, their arms bright and in good order and when they perform their exercises and evolutions with dexterity. "
Another good read is Adrian Goldsworthy's "The Complete Roman Army" which will give a more complete picture of what the army was like in different periods.

Sorry for being more homeworky then answerey, but happy to try and answer any more specific questions you might have!