I'm 28, dh is 31, and we've never paid into a private pension, and don't intend to.
I have a pension at work that makes an 8% contribution and dh's work pension pays in 4% (at no cost to us), but I have no idea what they're worth, or will be worth...they're free anyway, so I don't really care.
I don't trust pensions, and personally feel they're one of the riskiest things you can do with your money. For those in their 20s/30s now...do you really look at what the Government are deciding for private or state pensions now, and truly believe that it will have any relevance to you? Yes, they may well shake things up, make huge improvements, introduce a new rule to say you can withdraw £x as cash...and in 20 years we may have another, worse, financial disaster, pension pots will go through the floor and the new Government in 2034 will decide some more radical changes that puts pensions in a worse position than they are even now.
DH and I have a small buy-to-let which brings in £400pm rent. We don't make anything atm because the rent only just covers the mortgage on it, but that won't last for ever. Our plan is to overpay our mortgage (on our home) now, to pay it off as soon as possible. Then when it's clear, spend a couple of years saving that mortgage money towards a deposit for another mortgaged buy to let, then another...etc. Then we'll either have assets we can sell off, or a steady rental income.