diff --git a/main.go b/main.go
index faf31a5..f45fce6 100644
--- a/main.go
+++ b/main.go
@@ -635,49 +635,67 @@ func newProxyDialContext(dialTimeout time.Duration) DialContext {
 // tlsClientSessionCacheSize is the cache size for TLS client sessions.
 const tlsClientSessionCacheSize = 100
 
-type RoundTripperWrapper struct {
-	enableTLS bool
-	ctx       *cli.Context
+type roundTripperWrapper struct {
+	enableTLS       bool
+	cacert          string
+	clientCert      string
+	clientKey       string
+	insecure        bool
+	rwLocker        sync.Mutex
+	transport       http.RoundTripper
+	latestCacheTime time.Time
 }
 
-func (rtw *RoundTripperWrapper) RoundTrip(req *http.Request) (*http.Response, error) {
-	tr := &http.Transport{
-		Proxy:                 http.ProxyFromEnvironment,
-		DialContext:           dialContextWithDNSCache(dnsCache, newProxyDialContext(10*time.Second)),
-		MaxIdleConnsPerHost:   1024,
-		WriteBufferSize:       32 << 10, // 32KiB moving up from 4KiB default
-		ReadBufferSize:        32 << 10, // 32KiB moving up from 4KiB default
-		IdleConnTimeout:       15 * time.Second,
-		TLSHandshakeTimeout:   15 * time.Second,
-		ExpectContinueTimeout: 15 * time.Second,
-		// Set this value so that the underlying transport round-tripper
-		// doesn't try to auto decode the body of objects with
-		// content-encoding set to `gzip`.
-		//
-		// Refer:
-		//    https://golang.org/src/net/http/transport.go?h=roundTrip#L1843
-		DisableCompression: true,
-	}
-
-	if rtw.enableTLS {
-		// Keep TLS config.
-		tr.TLSClientConfig = &tls.Config{
-			RootCAs:            getCertPool(rtw.ctx.GlobalString("cacert")),
-			Certificates:       getCertKeyPair(rtw.ctx.GlobalString("client-cert"), rtw.ctx.GlobalString("client-key")),
-			InsecureSkipVerify: rtw.ctx.GlobalBool("insecure"),
-			// Can't use SSLv3 because of POODLE and BEAST
-			// Can't use TLSv1.0 because of POODLE and BEAST using CBC cipher
-			// Can't use TLSv1.1 because of RC4 cipher usage
-			MinVersion:               tls.VersionTLS12,
-			PreferServerCipherSuites: true,
-			ClientSessionCache:       tls.NewLRUClientSessionCache(tlsClientSessionCacheSize),
+func (rtw *roundTripperWrapper) RoundTrip(req *http.Request) (*http.Response, error) {
+	rtw.rwLocker.Lock()
+	defer rtw.rwLocker.Unlock()
+	if rtw.transport == nil || time.Since(rtw.latestCacheTime) > time.Minute {
+		tr := &http.Transport{
+			Proxy:                 http.ProxyFromEnvironment,
+			DialContext:           dialContextWithDNSCache(dnsCache, newProxyDialContext(10*time.Second)),
+			MaxIdleConnsPerHost:   1024,
+			WriteBufferSize:       32 << 10, // 32KiB moving up from 4KiB default
+			ReadBufferSize:        32 << 10, // 32KiB moving up from 4KiB default
+			IdleConnTimeout:       15 * time.Second,
+			TLSHandshakeTimeout:   15 * time.Second,
+			ExpectContinueTimeout: 15 * time.Second,
+			// Set this value so that the underlying transport round-tripper
+			// doesn't try to auto decode the body of objects with
+			// content-encoding set to `gzip`.
+			//
+			// Refer:
+			//    https://golang.org/src/net/http/transport.go?h=roundTrip#L1843
+			DisableCompression: true,
 		}
+
+		if rtw.enableTLS {
+			// Keep TLS config.
+			tr.TLSClientConfig = &tls.Config{
+				RootCAs:            getCertPool(rtw.cacert),
+				Certificates:       getCertKeyPair(rtw.clientCert, rtw.clientKey),
+				InsecureSkipVerify: rtw.insecure,
+				// Can't use SSLv3 because of POODLE and BEAST
+				// Can't use TLSv1.0 because of POODLE and BEAST using CBC cipher
+				// Can't use TLSv1.1 because of RC4 cipher usage
+				MinVersion:               tls.VersionTLS12,
+				PreferServerCipherSuites: true,
+				ClientSessionCache:       tls.NewLRUClientSessionCache(tlsClientSessionCacheSize),
+			}
+		}
+		rtw.transport = tr
+		rtw.latestCacheTime = time.Now()
 	}
-	return tr.RoundTrip(req)
+	return rtw.transport.RoundTrip(req)
 }
 
 func clientTransport(ctx *cli.Context, enableTLS bool) http.RoundTripper {
-	return &RoundTripperWrapper{ctx: ctx, enableTLS: enableTLS}
+	return &roundTripperWrapper{
+		enableTLS:  enableTLS,
+		cacert:     ctx.GlobalString("cacert"),
+		clientCert: ctx.GlobalString("client-cert"),
+		clientKey:  ctx.GlobalString("client-key"),
+		insecure:   ctx.GlobalBool("insecure"),
+	}
 }
 
 func checkMain(ctx *cli.Context) {