@havoc
When it comes to dust, desktops will attract a lot more dust especially since they will have a lot more heavy-duty intake fans with high CFM, and even cabinets with dust filters, you will have specks of dust everywhere inside.
For the thermal paste, unless you see clock speed instability or throttling you do not need to reapply. Since, unlike other parts, the area where the thermal paste is applied is enclosed, if you get a reputed TP once applied it should last you easy about 3 years+, obviously, this statement will be false if you overclock, mine on your desktop or do anything that might push the load for prolonged hours.
Apart from that, I'd recommend cleaning or dusting out your Desktop (you don't need to remove parts), at least once every 3 or 6 months, and a simple brushing down on filters every 4 weeks.
I edit 1440p-100fps footage shot on
Sony A7III. I have 24GB of DDR4 RAM, and it easily spikes to 90% usage on a medium edit depth.
I don't keep any application running in the background either.
This is the first time seeing someone that abstains from sharing his/her media. Obviously, we can respect your privacy, and whatever you do, all the best.
Initially, when I came to this forum I had a lot of free time mostly since my work was WFH but then later I got promoted to a different department and now my shift timings ended up getting rotational and compulsory office visits lol. Let me tell you, never work in a field of networking there will always be people with issues or backbones to fix.