Is it worth having a clone disk?

[ppppenguin]

SSDs don't go on for ever but you're unlikely to exceed the write cycle limits with an ordinary personal workload for many years. With a drive used only for backup I find it hard to think that you'd get anywhere near the write cycle limits in the practical lifetime of either yourself or the SSD.

I think you may have had a random SSD failure rather than wear out. I would stick to Samsung or Crucial for SSDs. I'm sure that some other makes are good, but these are the leading brands with a good reputation for reliability.