Concrete Repair vs. Concrete Replace
Depending on the state of your concrete, you may be better off repairing the concrete instead of replacing it; and sometimes, it's the opposite.
In general, complete concrete removal and replacement is your best choice when the concrete has several wide, deep cracks that are starting to settle on one side or are uneven, if part of the concrete is pushed up thanks to cold weather, or if the concrete is settling due to improper grading preparation. In these instances, it's best to replace the concrete rather than repair it.
On the other hand, if there are just thin, hairline cracks with no evidence of settling, or the concrete is sunken because of excess weight being placed on the concrete, you should just repair the concrete, as it will be the fastest and most cost-effective option.