Also how long did your NB size covers fit for? and did you still use 6-8 covers when you moved up to the small size covers ohhhh and one more question what brands do you have and like the best? THANKS
Depends on the brand and how big your bub is. I had bambino mio NB PUL covers that were still fitting at 3 months using a NB fitted nappy. Motherease rikki NB PUL covers still fit my bub at 4 months. I didn't have BBH NB covers, but the small NB covers really only starting to fit now. Maz-a-licious NB covers still fit at 4 months.

Are you going to use prefolds or flats later on, or move on to MCNS? If you are going to try MCNs, don't buy too many covers in the next size up because you might find you like all-in-ones or pockets or another type where you don't need a cover.

6-8 covers is a good start. Some bubs poop often and others poop less. Some splatter and others don't. If you have a poop often, splatter baby you might want more covers. If i am out, it is also easier to take nappy and cover off together so i want a new cover for each nappy change. But 6-8 will get you started til you work out what you like.