Accident cases such as a slip and fall on premises often have liability issues which must be sorted out before settlement.
For example, if you slip, fall, and hurt yourself in a supermarket, the question is whether the supermarket had a reasonable system of inspection for slip hazards and whether it was being carefully implemented. It can take some legal procedures to get answers.
Aside from that, the usual advice in injury cases applies, namely it is not prudent to settle the case before the client has attained the point of maximum medical improvement, and a doctor is able to state a prognosis for the future. This can range from months to years.