Hello Jason,
Technically you warranty is only supplied by your seller, anything that applies post sale is a guarantee.
Is an extended guarantee worth it. there is no simple answer, because if nothing fails, then you have spent your money and had no benefit, conversely another van may have many faults, in which case the money has been a good investment. The problem is you cannot predict what might fail.
However, look at your experience over the last three years. Have you been fault free, or most of the problems you have experienced in the first year? if so then it is likely that all the teething problems have been sorted, so now what is left is general wear and tear.
On the other hand if you have had a succession of faults spread across the three years, it might indicate that some of the items are prone to continuing failure on into the future.
Only you can make that judgement call based on your own experience.
I would add that a number of consumer watchdogs, have often commented that such extended guarantee's are not worth it.
Looking at it from another perspective, these extended guarantees are in fact insurance policies. What you pay up front is a premium, but it also is shared with the manufacturer. This actually takes money out of your pocket and puts it into their coffers, for something that they hope will never occur
I personally aloways shy away from these schemes, but for some teh knoledge that they will have no large bills comming thier way may be a necessary comfort.
It may be woth asking varius other insurance companies if they offer similar schemes, you may find one cheaper.
Its your choice.