My mechanical timer is more than 15 years old, it still turns my lights on and off every day, it never fails, unless there is a power outage, which is very rare where I live, but then I just need to reset the time. I've used it on many different systems over the years, its been very reliable for me.
My wifi timers are 4 years old, have never failed yet. It re-sets itself after a power outage, which again, doesn't affect me.
If I had to buy new ones, I would probably buy the wifi ones, they are widely available, smaller than the mechanical ones, and very inexpensive these days.