I only say replacing your wheel bearings only because ive had cars come in for a simple replacing of a stud or (s) and turns out that I take everything apart and balls just drop and fall on the floor. If its usally a high miliage car like over maybe 60K iam guessing I would go ahead and spend or save up and wait to get it all replaced.

I dont know if your replacing one or more but you can ride on only 3 it will not affect anything and is safe. Two is good even, fine if you dont drive crazy. Like fast turns but not suggested.