A store is a handful of templates that get reused across hundreds of products, not a set of pages. Designing the right five things is most of the job.
Most stores need the middle one. Agencies tend to recommend the third because it bills better, so it's worth knowing the difference before anyone quotes you.
Route 01
Right whenYou're starting out, testing whether the products sell, or the brand isn't settled yet. Perfectly respectable and easy to move on from later.
Route 02
Right whenAlmost always. A good theme handles the mechanics and the customisation makes it yours, without paying to rebuild a cart from scratch.
Route 03
Right whenYou have unusual requirements a theme genuinely can't handle, or you're large enough that small percentage gains are worth the investment.
One thing worth understanding about route three: a custom theme means you own the maintenance. Paid themes get updated when Shopify changes something, and a custom one doesn't unless you pay someone. That ongoing cost rarely appears in the original quote.
Design one product page and you've designed all four hundred. That's why the effort goes into a small number of screens that get used constantly.
The template
Used for every product you sell. The single most important screen in the store.
What it has to handle
Products with one image and products with twelve. Long descriptions and short. Options, sizes, out of stock, and reviews. It has to look right in all of those states, not just the one used in the mockup.
The template
How people browse. Also the page most likely to rank in search for category terms.
What it has to handle
Collections with six products and collections with six hundred. Filtering that's usable on a phone, and room for real content above the grid rather than just a heading.
The template
The last screen you fully control before Shopify's checkout takes over.
What it has to handle
Shipping cost shown or estimated before checkout, since unexpected postage is the most common reason carts get abandoned. Editing quantities without a page reload.
The template
Less important than most store owners assume, since much of your traffic lands elsewhere.
What it has to handle
Routing people to the right collection quickly. A big banner and a slideshow is the default and it's rarely the best use of the first screen.
The template
The screens nobody designs, seen by people who are already looking to buy.
What it has to handle
Search results that look like the collection grid rather than a plain list, and a no-results screen that suggests something instead of ending the visit.
Number five is the one that gets skipped and it's a real cost. People who use a store's search are considerably more likely to buy than people browsing, and sending them to a bare "no results found" page loses exactly the visitors you most wanted.
Themes handle far more than people expect and there are a few genuine walls. Knowing where they are stops you paying for a custom build you don't need.
The checkout limit is the one people care about and it matters less than expected. Shopify's checkout converts well because it's been tested across an enormous number of stores. Wanting to redesign it is usually a branding instinct rather than a commercial problem worth solving.
Every app you install adds its own interface to your store, styled the way its developer decided rather than the way your store looks.
Review widgets and popups load their own type. A visitor sees three typefaces on one page without knowing why it feels off.
An app's blue button next to your brand colour, in a different shape and size. Small individually, obvious once there are four.
An app injects a block where it wants to sit rather than where it fits, most noticeably on phones.
A discount popup, a cookie notice, and a chat bubble all appearing at once, covering the product someone came to look at.
Most of this is fixable by styling the apps to match rather than accepting their defaults, and it's part of the design work rather than an extra. The other half of the problem is what apps do to your loading speed, which is covered under Shopify SEO.
On a live store taking orders, so nothing goes live without a way back.
Where people currently drop off, which collections earn, and what your real product range looks like rather than the tidy version.
Theme chosen for what it handles well, not how the demo store looks. The demo is always photographed better than your products.
Product and collection first, at phone width, tested against your messiest real products rather than an ideal one.
Everything happens on a duplicate theme, gets checked, then publishes in one step. Your live store keeps selling throughout.
Probably not. A good paid theme with real customisation gets most stores everything they need, at a fraction of the cost and with updates handled for you.
Custom becomes worth it at scale, where a small percentage improvement is worth a lot of money, or where you genuinely need something no theme supports. We'd say which situation you're in after looking at the store.
Usually, and it's often the cheapest route to a real improvement. Plenty of stores have a decent theme that was never set up properly.
Where we'd suggest changing is when the theme is abandoned by its developer or so heavily modified that updating it would undo the work.
That's a design decision we make deliberately. Sections stay editable in Shopify's own editor so your team can change text, images, and ordering without calling anyone.
Custom code that locks you out of your own store is easy to write and we avoid it. Ask any agency this question before signing, because the answer varies a lot.
Generally no. They add weight to every page and they tie your layouts to a subscription, so cancelling can break the pages you built with it.
Shopify's own sections do most of what people want a builder for. We'd rather build sections properly than add a dependency you're stuck with.
A customised theme is usually weeks rather than months. What extends it is product photography and descriptions, not the design work.
If your product content isn't ready, that's the thing to start on now, because it's the part that holds up every store project.
A theme change alone usually doesn't, because Shopify keeps your URLs. What causes problems is removing content from collection pages because it cluttered the design.
If you're moving to Shopify from another platform, that's a different situation with real risk, covered under SEO migration.
Scoped from your store rather than quoted blind, since a theme setup and a custom build are very different jobs. Pricing sits on the main web design page.
Related services
Thirty minutes on where it's losing people and whether a theme change is even the answer.
Or email hello@culmen.digital