If you are going to repaste the laptop. I would avoid most of the top 5 regularly recommended thermal pastes and go with either SYY-157 or Honeywell PTM7950 if you can afford it.
Reason behind this is because of a thing called 'pump out' where thermal paste gets
pushed or
squeezed out from the mating surfaces with very little remaining where it should be.
For example...
All the thermal paste leaked out around the die but very little remained on it....
A lot of thermal pastes are too watery and gets pushed out easily. SYY-157 is a lot thicker in consistency than MX-4 and as far as I have read, doesnt suffer from pump out where as even kryonaut being as awesome of a paste it is pumps out after 6-8 months. SYY will run perfectly fine until your laptop's next maintenance cycle where you open it up to clean out all the dust build up. Be it one or two years inbetween.
SYY is significantly cheaper than kryonaut but doesnt cool as good as kryonaut or MX-4 but most of them are within the same ball park between 2-5'c difference with one another.
If you are choosing to keep the laptop for a long long time I would consider getting Honeywell ptm7950. It costs as much as Kryonaut but lasts forever and you will never need to repaste your laptop ever again as it doesnt suffer from pump out. Im considering doing this with my own laptop too but im still in my research phase and my laptop isnt overheating yet.