Which is better, upgrade or clean install?

I am use to having one version installed and then updating it. Then when a new version comes a long I uninstall the old version completely and then install the newer one and then bring in my settings or adjust them like Firefox, Avast, etc.

I am on Win 10 1511 and never got around to reading up on this for going up to 1607 and then to the top at 1703. I read about downloading the ISO's here. What I am not sure of if it is easier just to upgrade to 1607 and then to 1703? Or is it just better to download the ISO of 1703, wipe my SSD out and then install 1703 cleanly?

I ask because it just seems like things of the past do not pertain to today because things got better. SSD's of old needed tweaking, today just load Win10 and run. Just wondering if upgrading is better than doing a whole system wipe then install. Also, I think I know this, but just making sure. I bought my Windows 10 when it was first released with it's key. If the wipe drive and install cleanly is the way then that same key will still work?

Thanks

Thanks for the quick reply swarfega. I almost forgot about ninite, that would be good. Firefox profiles are backedup, my files are backedup, have a list of programs installed so easy to find.

What do you think, better to do 1607, play with it for a while and then wipe it out again to get to 1703? Or just go to 1703? Also, will my key work if I do what we are talking about? In my mind it should, but just want to make sure with folks who have done what I am about to embark to do.

Done it both ways, Clean install (keep my files, in some cases).

With Upgrading, it seems there is usually some gremlin, that shows up sooner or later.
Keeping images is the best practice to employ too !

Clean install all the way.......Just make up the MCT on a USB stick and go straight to 1703......As stated Ninite is GTG and one thing that makes your browser bookmarks/favorites easy to recover is export your bookmarks/favorites say to your desktop then onto a USB stick which will be the "bookmarks.html" file then just import it back into which ever browser you are using(Firefox,IE 11,Chrome)and you instantly have them all back again.

I did the upgrade on one of my PCs and it took like 1 1/2 hrs even though I did not loose anything but compared to a clean install (Especially on a SSD) it takes me about 30 minutes or less for a clean install.

AddRAM said:

... although others have reported no issues using the upgrade method...

I am one of those 'others'. I have little choice if I want to keep using the OEM-installed copies of Office on my machines

So far the upgrade history is OEM Win7 > 1507 > 1511 > 1607 > 1703. No problems to report, and surprisingly there's no apparent build up of 'crap' - still seems to run as fast as a clean install.

If my system is currently running well, I just let it upgrade. I only really do clean installs when I have installed too much junk on my computer that I want to get rid of. As @Bree posted there is surprisingly little junk Windows leaves behind. I just run the disk cleanup command once a week or so and there isn't that much build up of old Windows files. I have this saved as a .bat file on my desktop that I run as administrator once a week or so:

%SystemRoot%\System32\Cmd.exe /c Cleanmgr /sageset:65535 & Cleanmgr /sagerun:65535

Thanks to everyone for your responses (and Happy Father's Day for those). I usually make images of my systems and they have some in handy, but I also do data backups for those once in a while when "the man" shows up and ruins something in my system. But I hear you all. For me it just seems that starting clean seems to keep thing in order. Firefox always leaves something, case point my stock program stopped working. Finally nuked it, cleaned my system, installed latest and then imported back my settings and then my stock program worked again and has still till today. But as I said it does seem upgrading has gotten better so just wondering.

Thanks for everyone's input, I think I will just upgrade to 1703 and bypass 1607 as mentioned.