In my opinion 30 years is a long time for a mortgage. Take this example. I'm only 29 years old and have about 5 months to go before I turn 30 so I haven't existed on this planet for 30 years yet.
If my parents took out a 30 year mortgage to buy a home when I was born they'd still have 5 months left to pay on the mortgage.
Or another example we lost our home in the year 1994 when I was 4 days away from turning 6 years old. We were renting a house for 6 of those months until my dad got a mobile home brought in and placed on the ground where our house burnt.
He bought it with cash from the insurance money.
So if my parents had bought another home elsewhere and got a 30 year mortgage in the year 1994 they would still have 7 years left to pay off the home mortgage.
1994 was a long time ago to me and that was only 23 years ago.
When I bought my house it was for 10 years and I have 7 more to go. That seems a long way off to me so I wouldn't want a 30 year mortgage.
You can however take out a 30 year mortgage and pay more on the payments to have the house paid off sooner than 30 years.