I have an iPhone 6se with 128gb memory and 92gb of unused memory.
What I have done for years now is when I get a call I add it to my phone. Goes like this.
Get call from 555-555-5555, can be either possibly good tenant or you know it is bad.
I record them like this, I ask for their first and last name, ask them to spell it and EVERY entry is recorded like this on the first name slot in my phone.
Temp C+ has DOG, HUD John Doe & 3 kids
Notice I use 'Temp' as first item to separate these contacts from my real contacts. I make pertinent notes in first name line. I give them a rating and few important notes. On last name line I put date. I have never had to delete any because of memory space.
1/26/2022 10/12/2020 1/4/2018
You would be surprised how many calls I've had over the years from the same people but they change their phone number. This is where the date comes in handy. They are very surprised when I ask them questions of how their information has changed over time and they think I have a photographic memory, LOL. Then I go down to the notes section on every contact to make additional notes about this potential tenant and put the date relevant to when I got the new data. Some I block after making notes, most I don't block because I now have a heads up when they call their information I recorded in the first name position scrolls across my phone screen when they call. I then choose to answer or let go to voice mail.
Also if this person does become an actual tenant I change the first name line to this:
Ten 123 Main St. John & Jane Doe, HUD, DOG
This gives me a heads up I'm getting a call from a tenant and couple of hints about them in case I don't recall at that time and the date tells me how long they've been with me as a tenant. All works pretty well as we have quite a few tenants and my memory ain't what it use to be.
Last time I checked I have over 6,000 contacts in my phone and as you can see with PLENTY of memory to spare and that is with 2,000 photos and 100 videos too boot.
This takes a minute or 2 per contact but I have found it to be very useful in the long run.
I also would like to hear what other methods folks do and use. One I would love to have is ability to record phone calls on the phone without having to put call on speaker and use a digital voice recorder. That method works but is a bit cumbersome and has drawbacks. Missouri is a state that as long as one party in the conversation knows it is being recorded is completely legal and admissible in court. I have used this in past and has been very useful.
Good luck --192.129.xxx.xx