2. The next thing you want to check is that they are well hydrated and undamaged. The petals should appear firm and plump, avoid any that appear limp or veiney. Now look over the stems, checking for any that are bent, broken or pinched. The blooms won't last long if they can't get water and nutrients.
3. To be sure the flowers are free of insects and disease you should inspect the leaves. Look for holes where they have been chewed on and any spotty patterns or powdery residue.
4. Finally, check the stems and lower leaves for any signs of decay. If they have been left to sit in unchanged water for too long they may be starting to rot. Make sure they aren't beginning to turn yellow or brown.