A Little Help With Player Prefs

I always have a little difficulty understanding player prefs. I have a scenario where I need to retrieve some information stored in player prefs like this:

 public static void SetStartDate()
     {
         UserInformation.startDate = System.DateTime.Now ; //save the start date ->
         PlayerPrefs.SetString("DateInitialized", UserInformation.startDate.ToString()) ;
         Debug.Log ("Setting Start Date Now");
     }

Here is the UserInformation script

 using UnityEngine;
 using System.Collections;
 
 public class UserInformation : MonoBehaviour {
 
     public static string LastThingSaid01{
         get; set; 
     }
 
     public static string LastThingSaid02{
         get; set; 
     }
 
     public static System.DateTime startDate;
     public static System.DateTime today;
 
 
 
     /*public static void SetStartDate()
     {
         startDate = System.DateTime.Now ; //save the start date ->
         PlayerPrefs.SetString("DateInitialized", startDate.ToString()) ;
         print ("Setting Start Date Now");
     }*/
 
     public static string GetDaysPassed()
     {
         today = System.DateTime.Now ;
 
         //days between today and start date -->
         System.TimeSpan elapsed = today.Subtract(startDate) ;
 
         double days = elapsed.TotalDays ;
 
         return days.ToString("0") ;
     }
 }
 

Basically what I want to do is get the "Start Date" and use that in an if statement something like:

 if (DaysPast == 1){
 Do Something
 }

But I'm not quite sure how to access that properly?? In My Load Script I have this:

 using UnityEngine;
 using System.Collections;
 
 public class LoadInformation {
 
     public static void GetStartDate()
     {
         UserInformation.startDate.ToString( PlayerPrefs.GetString ("DateInitialized"));
     }
 }
 

I was able to get a debug to show the start date but I'm still not certain how to use that in an if statement like I mentioned earlier??