How come you buy/build a PC with all the current hardware and it speeds along happily. Six years down the line it ends up all bloated and sluggish when nothing has changed, same software, same web browser, nothing else. CCleaner, etc, ran regularly but just goes slow again after a day.
Is it some conspiracy theory to make you get a new machine with the current up to date tech, just for the same thing to happen again a few years down the line...?
I'd argue that in that time, almost all PC's do in fact change. More than you think. Just through general usage things are changing and getting "clogged up". Temp files from installations, new programs, updates to software, updates to the updates, updates to browser addons, updates to windows. More temp files. Temporary internet files. Caches filling up. An unclean shutdown here, an unclean shutdown there. A power cut. A crash causing ungraceful termination of processes. A tool bar here, a tool bar there. Accidental install of bloat bundled with legitimate software (eg imgburn). Fragmentation of files. Windows not being as robust as it could be.
It all adds up...
Most of this is not noticed now with SSDs, because they disguise slow down from such impeccable random access seek times.
I still have the same win 7 install from about 2010. Running fine to be honest.