Increasing reliability of a hardtail MTB What affects the reliability of bike more, better suspension or heavier tyres? I have bought a hardtail (Rockrider ST520) with 80mm front travel and 27.5 x 2.0 all terrain tyres. The bike is meant for slightly rugged trails but I intend on taking it out on some fairly rough ground, it will probably hold as I am only 60kg but what upgrades are possible to increase its strength and reliability, should I invest in a better fork or heavier tyres? I'm a college student so finances are how you would expect them to be.

There's no point replacing the fork. A better fork will be more robust but replacing a major component is not cost effective. A better fork will cost a significant fraction of the whole bike as a separate component. If you want a better fork you should have spent the money buying a higher spec bike in the first place.

Wider tires are relatively inexpensive and will definitely help smooth out the trails. Go tubeless if your wheels allow for it as this will allow running lower pressure without risking pinch-flats.