The $1,400 Mistake: What Happens When You Don't Check Your Rent Sheet

In September 2023, I missed a $1,400 rent payment for 11 days. Not because the tenant was hiding. Not because there was a dispute. I just forgot to check my spreadsheet.

That one oversight cost me way more than $1,400. Here's the full story.

What Happened

I manage 12 rental units in Colorado. All tracked in a Google Sheet. Rent is due on the 1st, grace period through the 5th.

September was chaos at my day job. Huge project deadline. I was in meetings from 7am to 5pm most days. Evenings were spent catching up on emails.

I checked my rent sheet on September 1st. A few payments were already in. Normal. I figured I'd check again in a few days to catch the stragglers.

I didn't.

Not on the 5th. Not on the 7th. Not on the 10th. Life just kept happening.

On September 12th, a Saturday morning, I finally opened my sheet with a cup of coffee. And there it was. Unit 4A. $1,400. Blank in the Date Paid column. Eleven days late.

The Conversation

I texted the tenant right away. "Hey Marcus, just noticed rent hasn't come through for September. Everything okay?"

He called me within 5 minutes. And the conversation was not what I expected.

"I thought you guys gave me an extension since I didn't hear anything." He was genuinely confused. Most months I'd text by the 6th if payment was missing. This month, silence.

Turns out he'd had a car repair on September 3rd. $800. He figured if the landlord wasn't asking about rent, maybe there was some flexibility. So he spent the remaining money on bills.

I don't blame him. From his perspective, silence meant it was fine.

The Payment Plan

Marcus didn't have $1,400. He'd spent it. We worked out a payment plan: $350 extra per month on top of his regular rent for the next 4 months.

He agreed. He was apologetic. He's actually a good tenant. Pays on time 11 out of 12 months. This was the exception.

But here's the thing about payment plans. They're stressful for everyone. Every month for the next 4 months I was tracking the regular rent AND the extra $350. Worried he'd fall behind. Worried I'd have to start an eviction process over what started as my own mistake.

He paid it all. Took until January. But those 4 months were not fun.

The Real Cost

People think the cost of missing a late payment is just the rent amount. It's not. Let me break it down.

The rent itself: $1,400. Yes, I eventually collected it. But I didn't have it when I needed it. My mortgage payment on that property is $1,100/month. I had to float October's mortgage out of my own pocket because the payment plan hadn't caught up yet.

Late fee I didn't charge: $70. My lease has a 5% late fee. But I felt weird charging it when I didn't even notice for 11 days. If I'd caught it on day 6, I would have charged it and the tenant would have expected it.

Time spent dealing with it: ~6 hours. The phone calls, the payment plan negotiation, the extra tracking each month, the follow-up texts. At even $30/hour (lowballing it), that's $180 of my time.

Gas and a drive over: ~$20. I drove to the property to have the payment plan conversation in person. Felt like the right thing to do.

The stress: priceless. Every first of the month for the next 4 months, I'd open my sheet and hold my breath. Did Marcus pay the regular rent AND the extra? Is he going to fall behind? Am I going to have to file? That kind of anxiety doesn't have a dollar amount but it's real.

Total hard costs: roughly $1,670. Total real cost including time, stress, and opportunity cost: closer to $1,800.

For more on the math behind missed payments, I broke it down further in the real cost of missing a late rent payment.

The Lesson

This wasn't Marcus's fault. He's a good tenant who made a human decision when he didn't hear from his landlord.

This was my fault. Or more accurately, it was my system's fault. I was relying on myself to manually check a spreadsheet every few days. And the one time I didn't, it cost me $1,800.

The spreadsheet had all the data. The formulas were showing the overdue payment. The conditional formatting was turning that row red. But none of that matters if nobody opens the file.

It's not about bad tenants. It's about bad systems. A system that depends on a human remembering to check every single day is a system designed to fail.

What I Changed

After the Marcus situation, I decided I needed my spreadsheet to tell ME when something was wrong. Not the other way around.

I tried a few things. Google Apps Script broke. Zapier was expensive and complicated. I eventually built RentGuard to solve this exact problem.

RentGuard connects to your Google Sheet and checks it every day. If rent is overdue past the grace period, it sends a text and email. Day 1. Not day 11.

If I'd had it in September 2023, I would have gotten a text on September 6th. "Unit 4A: $1,400 overdue. 1 day past grace period." I would have texted Marcus that morning. He probably would have paid within 48 hours. Before the car repair ate through his cash.

The difference between catching it on day 1 and day 11 was $1,800 and 4 months of stress.

For Other Landlords

If you're reading this and thinking "that won't happen to me," I get it. I thought the same thing for 2 years. I checked my sheet religiously. Until I didn't.

You don't need to use RentGuard specifically. But you need SOMETHING that alerts you when rent is late. Whether it's an app, a script, a virtual assistant, or a really persistent calendar reminder.

Because the cost of missing a late payment isn't just the rent. It's the cascade. The payment plan. The stress. The time. The damaged relationship. The sleepless nights wondering if your tenant is going to pay or if you're going to have to file.

$15/month for monitoring is cheaper than one missed payment. I learned that the hard way.

If this story sounds familiar, read why I stopped checking my rent spreadsheet every day. It's the longer version of what I changed and why.