When business and rental activity shows up at the tax desk

You’re cruising through individual returns when a client sits down and hands you a stack of paper. Somewhere in the mix, they casually mention Instacart. Not as a business. Not even really as a job. Just something they did.

Suddenly, the return doesn’t feel so straightforward.

Now you’re sorting through receipts, mileage notes, hours reports and platform summaries, trying to make sense of what belongs where. You need to determine whether this is self-employment income, identify deductible expenses, report everything accurately and make sure the client gets every deduction they’re entitled to. All while projecting confidence at the tax desk.

That’s the reality of business income when it shows up unexpectedly.

The challenge isn’t the form, it’s the decisions

Preparing Schedule C (Form 1040), Profit or Loss from Business (Sole Proprietorship), isn’t just data entry. It requires judgment. When clients don’t approach their activity as a business, they rarely organize it like one. That leaves you to make sense of incomplete records and apply tax law in real time.

Questions start piling up quickly.

• Is this a for-profit activity or a hobby?
• What accounting method applies?
• Which expenses are allowable as ordinary and necessary?
• How should mileage and other mixed-use expenses, such as phone use or supplies, be handled?

Tax software can calculate totals, but it can’t tell you how to evaluate messy, real-world information or which questions you should be asking. That responsibility falls on the preparer. 

For those who don’t regularly handle Schedule C returns, this is often where uncertainty creeps in.

The same uncertainty shows up with rentals as well

A client mentions a rental house almost as an afterthought. They don’t see it as a business, especially if they rented the house out only a few times during the year. There’s a spreadsheet, maybe a few receipts and possibly last year’s depreciation schedule, assuming it can be found.

Now the work shifts to evaluating the activity. You need to determine how it should be categorized, which expenses are deductible, how depreciation should be handled and whether any special rules apply. One decision can affect the entire return, and small missteps can have outsized consequences.

Again, it’s not about knowing where numbers go on Schedule E (Form 1040), Supplemental Income and Loss. It’s about understanding how to evaluate the activity before you ever start entering information.

Why these returns feel overwhelming

For preparers who mostly work on straight individual returns, Schedules C and E introduce something different. They introduce judgment calls that affect the entire return.

• Accounting methods
• Depreciation options
• Business use of home rules
• Hobby versus business determinations
• Rental activity classifications

Each decision point requires a working understanding of the rules and the confidence to apply them correctly. When you don’t encounter these situations often, it’s easy to feel unsure, even for experienced tax professionals.

Building confidence through structure and application

The key to handling these returns confidently isn’t memorizing every line of the forms. It’s having a structured way to think through the activity, recognize common issues, identify risk areas and understand where decisions matter most.

That’s where training that blends tax law with hands-on application makes such a difference. NATP’s Introduction to Sole Proprietors and Rentals Online Training walks through Schedules C and E line by line, using real-world scenarios to highlight common pitfalls and show how the rules apply in practice. That structure helps turn uncertainty into clarity.

Breaking the material into manageable pieces also matters. When complex topics are covered in bite-sized sessions, it’s easier to absorb the information and connect it to real-world client situations.

Turning uncertainty into confidence at the tax desk

When you understand how to evaluate business and rental activity, those unexpected moments feel different. Instead of scrambling to interpret a stack of paper, you know how to ask the right questions, identify issues early and guide the conversation with confidence.

You’re not relying on software to make decisions for you. You’re using it as a tool, backed by a solid understanding of the applicable tax rules.

Strengthening your foundation before peak filing season

Sole proprietors and rental properties are some of the most common tax situations preparers encounter, and they’re also some of the easiest places for uncertainty to slow you down. Strengthening your foundation in these areas can make tax season smoother for staff and clients alike.

If situations like the Instacart example sound familiar, NATP offers an Introduction to Sole Proprietors and Rentals Online Training (Feb. 17-20, 2026, 10 a.m. - 12 p.m. CT). The course walks through these scenarios in a practical, approachable way, covering Schedules C and E fundamentals through real-life examples and guided instruction. Case studies reinforce how business and rental activity shows up in practice and where confidence matters most.

Sometimes the biggest difference at the tax desk isn’t experience, it’s preparation.