The first thing you need to consider is when the last caulking was done, and what sealant was used for the process. This matters because different sealants have different lifespans, and if you are dealing with polyurethane, then you’re looking at 5 to 10 years. If your window is leaking and the last caulking was done eleven years ago and with polyurethane, then you definitely should be thinking of doing a full system replacement. This is because the sealant has clearly outlived its typical lifespan.

Silicone, unlike polyurethane, is able to withstand the elements for a bit longer. Because it is inorganic and therefore doesn’t not disintegrate under the effects of UV light and fluctuating temperatures, silicone sealant can last for up to 20 years and beyond. So if your window is leaking yet you used silicone sealant a few years ago, you might want to re-caulk just the one window.

If you do decide to go for a full system replacement, it is important to note that you do not have to do this all at once. You can opt for a multi-phased approach where the replacements are done over a number of years depending on the building and your budget.

The good news is that sealant manufacturers offer warranty for these products. For the polyurethane, the warranty is 5-10 years while for silicone the warranties tend to be 20 years.

The final decision on whether you should re-caulk a single window or replace the system entirely boils down to how long you intend to maintain the building. Keep in mind also that some warranties can be transferred to new owners while others cannot.

It is necessary to be level headed when comparing the short term and long term pros and cons of choosing a re-caulk over a replacement and vice versa. Key in mind should be the financial repercussions of choosing either of the two, after all numbers don’t lie.