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depends on the severity of impact and the angle of impact and the resilience of the tissues.
Another important factor is the hematoma
collection in tissues.
You can not help the initial three factors but you can reduce the hematoma size by immediately compressing the site of impact.
As the age advances the tissues become more lax and that causes the bruise to be persistent. Some persons have loose body composition others can have platelet dysfunction
that causes increased bruising.
Wish you a great health!