diff --git a/session/common.go b/session/common.go
index 98049be5..f75a3a9f 100644
--- a/session/common.go
+++ b/session/common.go
@@ -18,7 +18,6 @@ type commonData struct {
 
 	issuer user.ID
 
-	lifetimeSet   bool
 	iat, nbf, exp uint64
 
 	authKey []byte
@@ -35,7 +34,6 @@ func (x commonData) copyTo(dst *commonData) {
 
 	dst.issuer = x.issuer
 
-	dst.lifetimeSet = x.lifetimeSet
 	dst.iat = x.iat
 	dst.nbf = x.nbf
 	dst.exp = x.exp
@@ -83,11 +81,7 @@ func (x *commonData) readFromV2(m session.Token, checkFieldPresence bool, r cont
 	}
 
 	lifetime := body.GetLifetime()
-	if x.lifetimeSet = lifetime != nil; x.lifetimeSet {
-		x.iat = lifetime.GetIat()
-		x.nbf = lifetime.GetNbf()
-		x.exp = lifetime.GetExp()
-	} else if checkFieldPresence {
+	if checkFieldPresence && lifetime == nil {
 		return errors.New("missing token lifetime")
 	}
 
@@ -113,6 +107,10 @@ func (x *commonData) readFromV2(m session.Token, checkFieldPresence bool, r cont
 		return errors.New("missing body signature")
 	}
 
+	x.iat = lifetime.GetIat()
+	x.nbf = lifetime.GetNbf()
+	x.exp = lifetime.GetExp()
+
 	return nil
 }
 
@@ -137,7 +135,7 @@ func (x commonData) fillBody(w contextWriter) *session.TokenBody {
 		body.SetOwnerID(&issuer)
 	}
 
-	if x.lifetimeSet {
+	if x.iat != 0 || x.nbf != 0 || x.exp != 0 {
 		var lifetime session.TokenLifetime
 		lifetime.SetIat(x.iat)
 		lifetime.SetNbf(x.nbf)
@@ -243,7 +241,6 @@ func (x *commonData) unmarshalJSON(data []byte, r contextReader) error {
 // See also ExpiredAt.
 func (x *commonData) SetExp(exp uint64) {
 	x.exp = exp
-	x.lifetimeSet = true
 }
 
 // SetNbf sets "nbf" (not before) claim which identifies the time (in NeoFS
@@ -256,7 +253,6 @@ func (x *commonData) SetExp(exp uint64) {
 // See also InvalidAt.
 func (x *commonData) SetNbf(nbf uint64) {
 	x.nbf = nbf
-	x.lifetimeSet = true
 }
 
 // SetIat sets "iat" (issued at) claim which identifies the time (in NeoFS
@@ -268,11 +264,10 @@ func (x *commonData) SetNbf(nbf uint64) {
 // See also InvalidAt.
 func (x *commonData) SetIat(iat uint64) {
 	x.iat = iat
-	x.lifetimeSet = true
 }
 
 func (x commonData) expiredAt(epoch uint64) bool {
-	return !x.lifetimeSet || x.exp < epoch
+	return x.exp < epoch
 }
 
 // InvalidAt asserts "exp", "nbf" and "iat" claims.
diff --git a/session/common_test.go b/session/common_test.go
index fc6fb78b..4acde984 100644
--- a/session/common_test.go
+++ b/session/common_test.go
@@ -21,16 +21,15 @@ func Test_commonData_copyTo(t *testing.T) {
 	usr := usertest.User()
 
 	data := commonData{
-		idSet:       true,
-		id:          uuid.New(),
-		issuer:      usr.UserID(),
-		lifetimeSet: true,
-		iat:         1,
-		nbf:         2,
-		exp:         3,
-		authKey:     []byte{1, 2, 3, 4},
-		sigSet:      true,
-		sig:         sig,
+		idSet:   true,
+		id:      uuid.New(),
+		issuer:  usr.UserID(),
+		iat:     1,
+		nbf:     2,
+		exp:     3,
+		authKey: []byte{1, 2, 3, 4},
+		sigSet:  true,
+		sig:     sig,
 	}
 
 	t.Run("copy", func(t *testing.T) {
@@ -130,7 +129,6 @@ func Test_commonData_copyTo(t *testing.T) {
 		var dst commonData
 		data.copyTo(&dst)
 
-		require.Equal(t, data.lifetimeSet, dst.lifetimeSet)
 		require.Equal(t, data.iat, dst.iat)
 		require.Equal(t, data.nbf, dst.nbf)
 		require.Equal(t, data.exp, dst.exp)
@@ -139,7 +137,6 @@ func Test_commonData_copyTo(t *testing.T) {
 		dst.SetIat(200)
 		dst.SetNbf(300)
 
-		require.Equal(t, data.lifetimeSet, dst.lifetimeSet)
 		require.NotEqual(t, data.iat, dst.iat)
 		require.NotEqual(t, data.nbf, dst.nbf)
 		require.NotEqual(t, data.exp, dst.exp)
@@ -148,18 +145,14 @@ func Test_commonData_copyTo(t *testing.T) {
 	t.Run("overwrite lifetime", func(t *testing.T) {
 		// lifetime is not set
 		local := commonData{}
-		require.False(t, local.lifetimeSet)
 
 		// lifetime is set
 		var dst commonData
 		dst.SetExp(100)
 		dst.SetIat(200)
 		dst.SetNbf(300)
-		require.True(t, dst.lifetimeSet)
 
 		local.copyTo(&dst)
-		require.False(t, local.lifetimeSet)
-		require.False(t, dst.lifetimeSet)
 
 		emptyWriter := func() session.TokenContext {
 			return &session.ContainerSessionContext{}
@@ -167,7 +160,6 @@ func Test_commonData_copyTo(t *testing.T) {
 		require.True(t, bytes.Equal(local.marshal(emptyWriter), dst.marshal(emptyWriter)))
 
 		// check both are equal
-		require.Equal(t, local.lifetimeSet, dst.lifetimeSet)
 		require.Equal(t, local.iat, dst.iat)
 		require.Equal(t, local.nbf, dst.nbf)
 		require.Equal(t, local.exp, dst.exp)
@@ -178,8 +170,6 @@ func Test_commonData_copyTo(t *testing.T) {
 		dst.SetNbf(300)
 
 		// check that affects only dst
-		require.False(t, local.lifetimeSet)
-		require.True(t, dst.lifetimeSet)
 		require.NotEqual(t, local.iat, dst.iat)
 		require.NotEqual(t, local.nbf, dst.nbf)
 		require.NotEqual(t, local.exp, dst.exp)
diff --git a/session/container_test.go b/session/container_test.go
index c3ebb0fa..e322c843 100644
--- a/session/container_test.go
+++ b/session/container_test.go
@@ -395,6 +395,7 @@ func TestContainer_AppliedTo(t *testing.T) {
 
 func TestContainer_InvalidAt(t *testing.T) {
 	var x session.Container
+	require.False(t, x.InvalidAt(0))
 
 	nbf := rand.Uint64()
 	if nbf == math.MaxUint64 {
diff --git a/session/object_test.go b/session/object_test.go
index ecbd310e..1449fdaa 100644
--- a/session/object_test.go
+++ b/session/object_test.go
@@ -488,6 +488,7 @@ func TestObject_AssertObject(t *testing.T) {
 
 func TestObject_InvalidAt(t *testing.T) {
 	var x session.Object
+	require.False(t, x.InvalidAt(0))
 
 	nbf := rand.Uint64()
 	if nbf == math.MaxUint64 {