SSD's AFAIK aren't great for constant rewriting and such - they speed up writes and reads, yes, but over a period of time the 'cells' and such deteriorate to the point of unusability.
Yes, they have a finite life..... in exactly the same way as every other storage device
My 96GB Kingston SSD has been on for 8 months, 24 days, and has an estimated remaining life of 8 years & 5 months. Lifespan is really not an issue.
For a laptop they're a perfect fit.
- no moving parts, so immune to vibration & shock damage.
- significantly lower power consumption, so longer battery life.
- much faster, so waste less battery powering other components while waiting for disk access.