A golden rule is to replace your old possessions when it's no longer feasible to keep them. For windows, this could mean that you'll be better off finding new units if the originals simply aren't up to snuff anymore. Some of the signs that your windows aren't working, though, might be subtle, and you should most likely try to replace when you have the time to do so, before the windows are completely beyond repair.

If you want to do something about this, though, you'll need to start somewhere. Any of these tell-tale signs can be good signals that you need to take that initiative and go find new windows today. 

1. Leaking air
Ideally, you want your home to be snug, with tightly sealed windows that keep the air from seeping out. You can look at the windows themselves to see if there are gaps in the seals or if they don't close all the way. Some windows may have clear flaws in them that contribute to the leakage and leave your house less efficient.

However, it's not always easy to tell, and you might have to get specific, looking at the spaces around the windows and noticing the way air passes through it.

The Department of Energy also recommends "the dollar bill trick." According to the site, you shouldn't be able to pull a dollar bill out from under a closed window pane easily. Try this and see what kind of results you get to decide whether or not you need those new windows installed.

2. Broken mechanisms
There's no point in keeping the window if it's broken beyond what it's worth. Redfin suggested several examples of windows ceasing to function, such as not being able to close or lock. Whatever the problem, a persistent issue can give you serious reason to find a brand-new window that works perfectly.

Check your windows, too, because certain weather conditions might end up hurting them if they aren't up to the challenge. Forbes said that you should think about replacing your windows after a severe storm. Remember there are many ways that a window can break, and little things like a broken lock can be at the root of some big woes.

3. Mismatched style
Not all of the reasons to replace a window have to do with function. That same Forbes piece said that a stylistic change could be the cause, whether you've just bought a house and want to change the style or your ancestral home is in desperate need of a new look.

Whatever window styles you decide on, you'll need windows that bring substance as well as style. NewSouth Window Solutions is a leading provider for sturdy, attractive windows built to last.