It should be fine if the tube is still unopened or securely sealed.

https://litecomparison.com/arctic-silver-5-vs-thermal-grizzly-kryonaut/

LONG ACTION – Due to its unique and specialised structure, Kryonaut thermal paste does not dry out even at temperatures as high as 80° Celsius. SURPRISING EFFECTS – You may notice a drop in temperature after the first use of this thermal solution, which will reduce the loudness of your equipment and improve its comfort of use.

Because of its unique high-density filling of micronized silver and increased thermally conductive ceramic particles, Arctic Silver 5 provides a new level of performance and stability. There are Arctic Silver resellers all over the world. The Arctic Silver 5 premium thermal compound is the gold standard in the industry. Arctic Silver 5 is intended to work with a wide range of bond lines connecting modern high-power CPUs to high-performance heatsinks or water-cooling systems.

The surfaces of CPUs and heatsinks have minute pits and valleys, no matter how perfectly flat they appear. These holes and valleys trap air, which is one of the worst heat conductors known to man, and this is where thermal pastes come in. Thermal paste is designed for excellent thermal conductivity and is used to fill all of those small pits and valleys to allow molecule-to-molecule thermal contact. This results in lower temperatures, longer component life, and no burned-out CPUs. If you don't have a heatsink and thermal paste installed, it only takes seconds to irreversibly damage or kill your CPU. Thermal pastes are available in a number of different quality levels. Arctic Silver is frequently regarded as the best material available, whereas the material included with pre-built PCs or packed with CPUs and most heat-sinks is regarded as the bare minimum. When compared to standard pastes, Arctic Silver 5 promises to reduce CPU temperatures by 3-12°C, with most customers reporting a reduction of 10°C. In terms of how to put it together. If you can't find the manufacturer's website for the thermal paste you purchased, try the heat-sink manufacturer, the CPU manufacturer, or the internet in general. The Arctic Silver instructions can be found at http://www.arcticsilver.com/methods.html. After you've read up on the official method, you might want to look it up on YouTube to see how it's done in practise before attempting it yourself.

It should be fine if the tube is still unopened or securely sealed. Others have used it after 6 years with no issues, but that was with a brand new tube. Before you begin, make sure the connection between the heat sink and the CPU is clean. If you notice that your CPU's temperature is rising after using your own 10-year-old tube, I recommend replacing it. In fact, I'd recommend getting a new tube anyway. This tube is small and compact, and it will suffice for a few applications. Why waste time completing the task with your tube only to discover that it hasn't held up properly over time? Best regards.

I realise it's late, but it's still relevant. I'd say there are at least ten appropriate applications. Give it a 4-5 if you don't give a damn. I was able to repast my previous desktop's GTX 660ti and do my laptop's CPU and GPU twice because I wanted to see how well Kryonaut worked. I still have enough to finish all three, but my initial application on the CPU and GPU was the larger quantity that some people use for other pastes, but this paste heats up quickly and doesn't work well with too much. I've found that adding very little at a time and spreading until a paper thin coating forms on the surface of whatever you're glueing works best. Don't worry if your layer isn't perfect or even; the Heatsink will take care of it.