diff --git a/options/options.go b/options/options.go
index ec1bd96..8a1f494 100644
--- a/options/options.go
+++ b/options/options.go
@@ -30,12 +30,12 @@ type Options struct {
 	ClientID      string   `env:"ESI_CLIENT_ID" description:"EVE SSO client ID"`
 	RedirectURI   string   `env:"ESI_REDIRECT_URI" default:"http://localhost:3000/callback" description:"EVE SSO redirect URI"`
 	Scopes        []string `env:"ESI_SCOPES" default:"esi-planets.manage_planets.v1" description:"EVE SSO scopes (space-separated)"`
-	CacheValidity string   `env:"ESI_CACHE_VALIDITY" default:"PT20M" description:"ESI cache validity in ISO8601 duration (e.g. PT20M for 20 minutes)"`
+	CacheValidity string   `env:"ESI_CACHE_VALIDITY" default:"20m" description:"ESI cache validity in Go duration format (e.g. 20m for 20 minutes)"`
 
 	// HTTP timeouts
-	HTTPTimeout        string `env:"HTTP_TIMEOUT" default:"PT30S" description:"HTTP client timeout in ISO8601 duration (e.g. PT30S for 30 seconds)"`
-	SSOCallbackTimeout string `env:"SSO_CALLBACK_TIMEOUT" default:"PT30S" description:"SSO callback timeout in ISO8601 duration (e.g. PT30S for 30 seconds)"`
-	TokenExpiryBuffer  int    `env:"TOKEN_EXPIRY_BUFFER" default:"30" description:"Token expiry buffer in seconds"`
+	HTTPTimeout        string `env:"HTTP_TIMEOUT" default:"30s" description:"HTTP client timeout in Go duration format (e.g. 30s for 30 seconds)"`
+	SSOCallbackTimeout string `env:"SSO_CALLBACK_TIMEOUT" default:"30s" description:"SSO callback timeout in Go duration format (e.g. 30s for 30 seconds)"`
+	TokenExpiryBuffer  string `env:"TOKEN_EXPIRY_BUFFER" default:"30s" description:"Token expiry buffer in Go duration format (e.g. 30s for 30 seconds)"`
 
 	WebhookURL   string `env:"WEBHOOK_URL" description:"Webhook URL for notifications"`
 	WebhookEmail string `env:"WEBHOOK_EMAIL" description:"Webhook authentication email"`