It will be at least 100 high flights before you will have the skill to draw out all the performance that a modern entry level glider is capable of producing. Used paragliders can be great and they can be a nightmare. There are many things about a paraglider that require testing in order to determine their true air worthiness. Paragliders may be useable for as little as 300 UV exposed hours. At some point every paraglider is best retired.
Some gliders come with lines which can shrink, stretch, or have broken cores.
It can be difficult to tell if a paraglider has developed a porosity problem, fading isn't necessary for a glider to fail a porosity check. New gliders are wonderful. If you make the right choices they can be easy to trust, resell, repair, and enjoy. The number one consideration is the reputation of the manufacturer. When budgeting for your glider be sure and consider a harness that you can keep for a long time.