I did myself a spreadsheet on renting vs owning only to persuade myself on a foregone conclusion.
The break-even point was 12 hours a year, based on C-152 at c. £90 per hour wet vs a quarter share in a Cub/Aeronca/C140 type.
Access to the shared aircraft cannot of course be accounted for, but makes a large qualitative input into the equation.
I now own a one-quarter share in each of four of the above types, and still consider myself quids in. Access or the old "minimum hours" situation definitely no problem.
Irish Penny-Whistle player