Both big and little things mattered.
We were forced to file bankruptcy in 1993, two years after buying a house in partnership with a family member. Ruined our outstanding credit records, of course...took us years of budgeting and working hard to recover. But it did make us take the idea of retirement seriously!
Were very lucky that the state pension fund began running retirement seminars for members. We took three years of classes - one series was so full of info on the complex subject of financial planning, we took it all three years in a row! The classes really helped, plus I had worked in insurance and banking, so I was familiar with how to do risk management/appraisals.
It was hard to do budget planning for 15 yrs into the future, but we kept working on it. Lots of little disagreements but that actually helps 'clear the air', to know what's important to your partner vs what's important to you. Those are ALWAYS two different POVs, and compromise is essential.
What's important are not the decisions one makes, as much as going through the process together. You will be doing this your entire lives with one another, and you need a positive pattern established.
Eventually built a lot of leeway into our retirement budget, which was good as some expenses have climbed through the roof over the last 20+ years, such as food, utilities, travel, etc. Although we always focused on a good work/life balance in our careers, our financial decisions were made with consideration for the long-term. This included scenarios of 'what to do when things go wrong' and 'what to do when things go really, really, REALLY wrong.'
Spouse was able to retire early, a few years after I did. He retired just as the big recession hit, January 2010, but due to our planning it had no effect on us except making it a lot of fun to travel when it wasn't crowded! Being conservative about estimating our income sources worked out very well; our retirement income is now comfortably above what we had hoped for. We're grateful for being able to give more to good charities and help both friends and family members when needed. There are few worse feelings than knowing someone deserving whom you love needs some financial help, but you just don't have the extra dollars to offer.