Landlord Deposit Defender 🛡️

Security deposits are one of the most common landlord–tenant flashpoints. This skill structures the fight: a room-by-room condition inventory at move-in and move-out, a diff that separates fair wear and tear (which landlords must absorb) from chargeable damage, useful-life depreciation math that prorates any legitimate deduction, jurisdiction deadlines for returning deposits, and a generated itemized dispute letter.

Overview

Four commands in scripts/deposit_defender.py:

1. inventory — record room/item/grade(0–5)/note entries with a date and label ("move-in"/"move-out"); validates grades; normalizes to JSON.
2. diff — compares two inventories; classifies each change as improvement / fair wear / damage using the grading rubric, item age over the tenancy, and defect-type rules; flags disputable deductions.
3. prorate — applies the useful-life formula max_deduction = value × max(0, 1 − years_used / useful_life); shows the gap between a landlord's full-price demand and the lawful prorated amount.
4. letter — generates a full markdown demand letter: timeline, itemized rebuttal with prorated figures, jurisdiction deadline citation, request for itemized receipts, small-claims escalation notice. jurisdictions lists the built-in deadline table.

When to Use

• Moving in: build the evidence baseline before unpacking.
• Moving out: document condition, predict the landlord's deductions.
• A deduction letter arrives: classify each item (wear vs damage), prorate, and draft the rebuttal.
• "Can my landlord charge me for repainting after 3 years?" (Usually: only a fraction — see proration.)

Don't use for: legal advice (it's decision support), eviction disputes, rent-increase law, or small-claims court filing procedure — but the letter it produces is the exhibit you'd bring to one.

Quick Start

# Move-in inventory (repeat --item; grades 0 new … 5 destroyed)
python3 scripts/deposit_defender.py inventory --label move-in --date 2023-06-01 \
  --item "living room,paint,1,fresh repaint" \
  --item "bedroom,carpet,1,nearly new" \
  --item "kitchen,oven,2,light wear" --json > move-in.json

# Diff two inventories over the tenancy
python3 scripts/deposit_defender.py diff --move-in move-in.json \
  --move-out move-out.json --tenancy-start 2023-06-01 --tenancy-end 2026-02-15

# What is a carpet worth after 2 of its 8-year life, priced at $1,200?
python3 scripts/deposit_defender.py prorate \
  --item "carpet,1200,8" --tenancy-years 2.5

# Full dispute letter (California example)
python3 scripts/deposit_defender.py letter --move-in move-in.json \
  --move-out move-out.json --deposit 2400 \
  --deductions deductions.json --jurisdiction CA \
  --tenant "Jordan Reyes" --landlord "Acme Property Mgmt" > dispute-letter.md

# Deadline reference
python3 scripts/deposit_defender.py jurisdictions

How It Works

Grading rubric (0–5): 0 new · 1 excellent · 2 minor wear · 3 noticeable wear · 4 significant damage · 5 destroyed/missing.

Wear vs damage. A delta of ≤ 1 grade over a normal tenancy, or defects of a type that come from ordinary use (scuffed paint, worn carpet paths, faded blinds), classify as fair wear and tear — not chargeable in most jurisdictions. Larger deltas, or defect types outside ordinary use (burns, holes, missing fixtures, pet urine), classify as potential damage.

Proration. Even legitimate damage is limited by remaining useful life. With carpet (8-yr life) valued $1,200 after 2.5 years of use:

max deduction = 1200 × (1 − 2.5/8) = $825

A landlord demanding the full $1,200 is over-claiming by $375.

Deadlines. Most jurisdictions cap the time a landlord has to return the deposit or send an itemized statement — 14 to 60 days in the US, 10 days in the UK (protection scheme), etc. Missed deadlines often forfeit deductions entirely. The built-in table is a starting point; verify current local law.

Common Pitfalls

1. No move-in evidence. A move-out inventory alone proves nothing about pre-existing condition. Photograph everything, dated, at move-in.
2. Conceding "repaint" charges at face value. Paint has a short useful life (≈3 yr); after a multi-year tenancy the lawful deduction is often a small fraction — or zero.
3. Assuming the landlord's invoice is the fair price. Demand itemized receipts; replacement-price for a depreciated item is double-dipping.
4. Missing the deadline. If the itemized statement arrives late, say so in writing immediately — many jurisdictions make late claims worthless.
5. Arguing emotion, not items. The letter works because it is itemized, dated, priced, and cites the rules — mirror that in any reply.

Verification Checklist

• inventory rejects grades outside 0–5
• diff classifies a 1-grade paint change as wear, a burn as damage
• prorate on a fully-depreciated item returns 0 deduction
• letter contains timeline, itemized rebuttal, deadline citation
• jurisdictions lists your jurisdiction's typical window
• python3 scripts/test_deposit_defender.py → ALL TESTS PASSED

Decision support, not legal advice. Jurisdiction rules change; verify current local law before relying on any figure here.

MIT © 2026 Denis Voronin