Condesation between panes - replace glass, window, or insert?
newbie here - please forgive the ignorance.
I live in Massachusetts. Our home was built in 1996 and has the original windows which are Hurd windows.
I have at least 8-9 windows that have condensation between the window panes. There are some that are worse than others, but I can see that at least 8-9 windows are obviously affected, and I suspect that others may be affected as well, although it's hard for me to tell. It seems that it's easier to see the condensation at times, and more difficult at other times.
I'm trying to figure out what is the best thing for me to do to fix this problem. I understand that the condensation occurs due to a failure of the seal.
I understand that one option is just to replace the glass in the windows. Another would be to replace the actual window. Is replacing the window insert the third option? How do I know which of these options to pursue? I assume it's more expensive to replace the entire window than just the glass. I think the frames are okay, but I'm not an expert at all. Is there some advantage or disadvantage, other than cost, of replacing the entire window vs. just the glass?
I've been told that the seals start failing due to age, and once they start failing, it's likely that all the seals of all the windows will likely start failing. Is there any advantage to replacing all the windows now, even the ones that aren't affected yet? Or should I just replace them as they go? Is it going to look strange for the house to have the windows be different?
Also, how do I know what type of glass I have in the windows currently? I had initially planned on replacing just the glass and got some quotes from glass people. But one guy told me that I have clear glass, one told me that they were lowE, one told me that he wasn't sure, but recommended that I replace them with lowE even if they were clear glass. One guy told me that there's a law in MA that's been in place since the mid 80s that requires the windows to be lowE, and another guy told me that was untrue. I've googled and can't find any information about whether there is a law about this or not.
Thanks for any advice or tips.