50-years old

If this is a group, then it's 50 year olds.

I think 50 year old is still young. Stay frugal till you're 70 and then stop saving your money. Well that is my plan.

Oh wait, you just wanted to check to see if the text was correctly written. I think the dash is not needed between "50-year old".

Not to me it isn't. Advice to 50-year-olds, or 50-year-old people, or people who are 50 years old (no hyphen there). The advice is for the people, not their ages. When the age is an adjective that comes before the noun and modifies the noun, or when the age is a noun, hyphenate.

My eight-year-old neighbour wrote a poem about commas for National Grammar Day.

That 70-year-old with the purple hoodie loves Justin Bieber.

When the age is part of an adjective phrase after the noun, don't hyphenate.

Charlie Sheen is 45 years old

His twin sons are nearly two years old.

Thanks, centrox.