diff --git a/resolver/berkshelf/resolver.go b/resolver/berkshelf/resolver.go
index 20c7174..7919cda 100644
--- a/resolver/berkshelf/resolver.go
+++ b/resolver/berkshelf/resolver.go
@@ -39,3 +39,8 @@ func (r Resolver) Resolve(dst string) error {
 func (r Resolver) Name() string {
 	return "Berkshelf"
 }
+
+// InputFiles returns a list of files Berkshelf uses as input.
+func (r Resolver) InputFiles() []string {
+	return []string{"Berksfile", "Berksfile.lock"}
+}
diff --git a/resolver/dir/resolver.go b/resolver/dir/resolver.go
index 0b7bf34..b7309d9 100644
--- a/resolver/dir/resolver.go
+++ b/resolver/dir/resolver.go
@@ -41,3 +41,8 @@ func (r Resolver) Resolve(dst string) error {
 func (r Resolver) Name() string {
 	return "Directory"
 }
+
+// InputFiles returns a list of files the directory resolver uses as input.
+func (r Resolver) InputFiles() []string {
+	return []string{}
+}
diff --git a/resolver/librarian/resolver.go b/resolver/librarian/resolver.go
index a1475d1..6036670 100644
--- a/resolver/librarian/resolver.go
+++ b/resolver/librarian/resolver.go
@@ -25,3 +25,8 @@ func (r Resolver) Resolve(dst string) error {
 func (r Resolver) Name() string {
 	return "Librarian-Chef"
 }
+
+// InputFiles returns a list of files Librarian-Chef uses as input.
+func (r Resolver) InputFiles() []string {
+	return []string{"Cheffile", "Cheffile.lock"}
+}
diff --git a/resolver/resolver.go b/resolver/resolver.go
index 5c6f0d1..3d6566a 100644
--- a/resolver/resolver.go
+++ b/resolver/resolver.go
@@ -20,6 +20,7 @@ import (
 type Resolver interface {
 	Resolve(dst string) error
 	Name() string
+	InputFiles() []string
 }
 
 func findResolverByName(name string) (Resolver, error) {
@@ -41,23 +42,26 @@ func findResolver(name, dst string) (Resolver, error) {
 		return findResolverByName(name)
 	}
 
-	cb, _ := cookbook.NewCookbook(".")
+	tsFile := path.Join(dst, "action_resolve")
+	ts, _ := util.ReadTimestampFile(tsFile)
 
-	// If the current folder is a cookbook and its dependencies have
-	// already been resolved, only update this cookbook with rsync.
-	// TODO: improve this check by comparing timestamps etc.
-	if cb.Name != "" && util.FileExist(dst) {
-		return dir.Resolver{}, nil
-	}
-
-	if util.FileExist("Berksfile") {
-		return berkshelf.Resolver{}, nil
+	for _, name := range berkshelf.InputFiles {
+		mt, err := util.FileModTime(name)
+		if err == nil && mt >= ts {
+			log.Debugf("%s was updated, using Berkshelf\n", name)
+			return berkshelf.Resolver{}, nil
+		}
 	}
 
-	if util.FileExist("Cheffile") {
-		return librarian.Resolver{}, nil
+	for _, name := range librarian.InputFiles {
+		mt, err := util.FileModTime(name)
+		if err == nil && mt >= ts {
+			log.Debugf("%s was updated, using Librarian\n", name)
+			return librarian.Resolver{}, nil
+		}
 	}
 
+	cb, _ := cookbook.NewCookbook(".")
 	if cb.Name != "" {
 		return dir.Resolver{}, nil
 	}
@@ -102,6 +106,11 @@ func Resolve(name, dst string) error {
 		return err
 	}
 
+	tsFile := path.Join(dst, "action_resolve")
+	if err := util.WriteTimestampFile(tsFile); err != nil {
+		return err
+	}
+
 	log.Info("Stripping non-cookbook files")
 	return stripCookbooks(dst)
 
diff --git a/util/util.go b/util/util.go
index 6af4e6c..ec35a99 100644
--- a/util/util.go
+++ b/util/util.go
@@ -5,7 +5,9 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
+	"time"
 )
 
 // FileExist reports whether a file or directory exists.
@@ -57,3 +59,28 @@ func InTestDir(f func()) {
 	defer os.RemoveAll(testDir)
 	InDir(testDir, f)
 }
+
+// WriteTimestampFile writes the current time as Unix timestamp to a file.
+func WriteTimestampFile(filename string) error {
+	ts := strconv.FormatInt(time.Now().Unix(), 10)
+	return ioutil.WriteFile(filename, []byte(ts), 0644)
+}
+
+// ReadTimestampFile reads the Unix timestamp from a file created with
+// WriteTimestampFile.
+func ReadTimestampFile(filename string) (int64, error) {
+	data, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return 0, err
+	}
+	return strconv.ParseInt(string(data), 10, 64)
+}
+
+// FileModTime returns a file's modification time as Unix timestamp.
+func FileModTime(filename string) (int64, error) {
+	info, err := os.Stat(filename)
+	if err != nil {
+		return 0, err
+	}
+	return info.ModTime().Unix(), nil
+}
diff --git a/util/util_test.go b/util/util_test.go
index eaa1889..47b2995 100644
--- a/util/util_test.go
+++ b/util/util_test.go
@@ -6,6 +6,7 @@ import (
 	"path/filepath"
 	"strings"
 	"testing"
+	"time"
 
 	. "github.com/mlafeldt/chef-runner/util"
 	"github.com/stretchr/testify/assert"
@@ -76,3 +77,15 @@ func TestInTestDir(t *testing.T) {
 	assert.Equal(t, wd, wd2)
 	assert.False(t, FileExist(testDir))
 }
+
+func TestWriteAndReadTimestampFile(t *testing.T) {
+	tsFile := "some-timestamp"
+	defer os.Remove(tsFile)
+
+	err := WriteTimestampFile(tsFile)
+	assert.NoError(t, err)
+
+	ts, err := ReadTimestampFile(tsFile)
+	assert.NoError(t, err)
+	assert.True(t, ts >= time.Now().Unix())
+}