$5K WordPress refresh vs $20K custom build — performance alone does not justify the $15K delta

reference·Scope: business·Status: current

Created 2026-05-22

Decision framework for KW SMB clients deciding between a $5K WordPress refresh and a $20K custom build.

Stage 1 — do this regardless of which path:

Measure first. PageSpeed Insights / CrUX for top 5 pages. If already passing all three CWV thresholds on mobile (LCP <2.5s, INP <200ms, CLS <0.1), performance is not your highest-ROI investment. Spend on content, conversion design, GBP work instead.
Define your business KPI: form submissions, booked appointments, orders, calls.
Estimate upside. Using Deloitte's ~0.1s → ~1% conversion (calibrated down for non-retail), an SMB doing $150K/year online would gain ~$1,500/year per 100ms shaved.

Choose the $5K WordPress refresh if:

Current site clears or is close to clearing CWV thresholds.
Traffic under ~10,000 unique visitors/month.
Business is professional services, local commerce, or lead-gen — not a complex catalog or proprietary booking flow.
Modern theme (Kadence, GeneratePress, Blocksy) + quality managed host (Kinsta, WP Engine, Cloudways) + image optimization + plugin discipline + CDN can hit targets.
Budget split: ~$1.5K theme + setup, ~$1K hosting/CDN year 1, ~$1.5K image/perf/plugin audit, ~$1K content + conversion design.

Choose the $20K custom build if:

Measured INP issues a WordPress site can't solve (React-heavy interactive tools, complex configurators, real-time dashboards).
Transactional flow (multi-step booking, custom commerce, B2B quote builder) where the conversion path is the product.
Integration requirements (CRM, ERP, custom POS, B2B portals) exceed WP plugins' reliability.
$500K/year online — at that scale a 5-10% conversion lift is worth tens of thousands per year.

Benchmarks that would change the recommendation:

Mobile LCP >4s after a $5K refresh attempt → consider custom build or change hosts.
INP >500ms because of theme/plugin JS bloat → custom build becomes defensible.
$1M/year online → the $20K delta is rounding error; do the custom build properly.
Selling to enterprise B2B buyers (KW tech corridor, Communitech-adjacent) → site polish has signaling value beyond pure performance.