Start on Basic. For a new store, the higher plans mostly buy lower transaction fees and features you will not use yet, like extra staff accounts and advanced reports. The right time to upgrade is when your monthly sales make the fee math flip, not when the store launches. Almost every new merchant overestimates how much plan they need on day one.
The meaningful differences for a new store are the monthly fee, the credit card rates, and the transaction fee on non-Shopify Payments orders. Higher plans charge more per month but take a smaller cut per sale. Everything else, staff accounts, inventory locations, checkout customization on Plus, matters once the business is running, not while you are validating the idea.
Shopify Payments deserves a callout because it changes the math. Using Shopify's own processor removes the extra transaction fee entirely on every plan, which makes the plan choice mostly about the monthly fee versus the card rate. If you plan to use a third-party processor, factor the transaction fee into the comparison, because it adds up fast at volume.
Upgrading makes sense when the monthly savings on fees exceed the increase in the monthly plan cost. Take your expected monthly sales, multiply by the difference in card rates between plans, and compare that to the difference in monthly fees. If the savings are bigger, upgrade. If not, stay.
For a concrete sense of scale: the rate difference between adjacent plans is a fraction of a percent, so a store doing a few thousand a month in sales saves tens of dollars by upgrading while paying a much larger increase in the monthly fee. The flip point usually arrives well into five figures of monthly revenue. Until your sales say otherwise, Basic is the rational choice.
Consistent sales volume is the main signal. When the break-even math favors the higher plan for three months running, move up. The second signal is features: needing more staff accounts with real permissions, selling internationally with multiple markets and duties, or wanting checkout customization that only Plus offers. Upgrade for a feature you need this quarter, not one you might need next year.
Downgrading is also fine and underused. If a launch spikes and then settles, or a seasonal business drops back in the off-season, moving down a plan for quiet months is legitimate. Plans are monthly commitments, not identities. Match the plan to the business you have, and recheck the math quarterly.
Do not start on Plus. Plus is an enterprise product with enterprise pricing, and its checkout customization and API limits matter to high-volume or complex operations, not to a new store finding its first customers. Starting there burns cash that should go to inventory and marketing.
Do not pick a plan for the trial either. The trial is about building and validating, and the plan choice can wait until you are ready to remove the password page and take real orders. Choose when the store is real, choose with the math, and revisit as it grows.