Thermal Compound Efficiency Degrades Fast

[geo337]

I have a dell Inspiron N5110 with a core i5 processor and Nvidia graphics I changed the thermal paste about 5 months ago used Antec Formula 7 and the temps. dropped significantly (I stress tested both CPU and GPU at the same time for more than 30 min with core temps of approximately 95 degrees Celsius on the contrary with the 5 min 97 degrees I used to get before)
I used the spreading method in applying the paste I believe I have applied more than enough but now I have returned to the first state again what should I do?
Thanks in advance

 

[Someone Somewhere]

It's more often the fan/heatsinks being full of dust than the thermal compound. I'm guessing you cleaned the fans at the same time as you replaced the thermal compound?

 

[geo337]

Yes, I clean the fan and the heat sink about twice a month (I use a blower)