diff --git a/pybtc/connector/utxo.py b/pybtc/connector/utxo.py
index 9daf25a..a8efc02 100644
--- a/pybtc/connector/utxo.py
+++ b/pybtc/connector/utxo.py
@@ -77,9 +77,14 @@ class UTXO():
                     block_changed = True
                     lb = i[1][0] >> 39
                 if lb - 1 == checkpoint:
-                    if len(self.cached) > int(self.size_limit):
-                        if self.checkpoints:
-                            checkpoint = self.checkpoints.pop(0)
+                    if len(self.pending_utxo) < int(self.size_limit * 0.9):
+                        if len(self.cached) > int(self.size_limit * 0.9):
+                            if self.checkpoints:
+                                checkpoint = self.checkpoints.pop(0)
+                        else:
+                            if len(self.cached) > int(self.size_limit):
+                                if self.checkpoints:
+                                    checkpoint = self.checkpoints.pop(0)
                     else:
                         checkpoint_found = True
                 while self.checkpoints and checkpoint < lb - 1: