T8 Retrofit; Instant vs. Programmed Ballast

[cebury]

I'm retrofitting my T12 to T8 florescent bulbs. My current T12 bulbs (old magnetic rapid-start ballasts) in the kitchen last around 2-3 years each. They aren't on "all day" like an office, but they aren't on/off like a hallway light: probably closer to on/off than all-day since we are home during the day.

Question: If I switch to electronic Instant Start ballast and use T8 bulbs, how much reduced lifespan could I expect?

I'm debating on upgrading the ballasts to more expensive Programmed Start instead of the Instant Start (which are 50% the price).

Opinions?

[Sunking]

Question: If I switch to electronic Instant Start ballast and use T8 bulbs, how much reduced lifespan could I expect?

No difference T12, T8, and T5 are all rated the same 20,000 hours. What you are gaining is lighting efficiency expressed as Lumens/Watt.

T12 = 75 L/W
T8 = 95 L/W
T5 = 105 L/W

So you are gaining 21% more light per watt.

[cebury]

Hmm, maybe I didn't ask it correctly or my assumptions are wrong.

Is the lifespan of a T8 bulb reduced, when paired with an Instant Start vs. a Programmed Start ballast?
Stuff I've read says the answer is a clear Yes, when T8+Instant is used in frequent on/off fixtures. In an office, where lights are on all day, there is no reduction in life. Some say "T8+Instant Start = Death to the bulb unless it's hardly ever cycled, like no more than 2x/day".

If that's true, then I'll pay more and go with Programmed Start.

If an extreme exaggeration, then maybe I'll stick with the cheaper Instant-Start ballast.