The lifetime of a solar kit is determined by its 2 key components: the solar panels and the micro inverter.
High quality solar panel manufacturers generally guarantee production for 30 years. This means that your panels will produce electricity for at least that time according to the technical data sheet provided by the manufacturer. Likely they will do so a lot longer and produce more.
Micro inverters usually come with a 10 to 12 years warranty by the manufacturer. Also in this case it’s likely they will work a lot longer. A micro inverter is easy to swap out should this be required, to extend the lifespan of your kit for as long as the panels produce.
They say only true love lasts forever, but plugin solar kits can also give you a lot of love for a long time.