We are not in at all and never have been. Wasn't an option financially til this weekend now that we've caught up on so many bills.
I'm going to challenge you on this, because I think you still need to change your mindset a bit. The reality is that investing in your 401(k) was
always an option -- you just chose to use your money for other things, like activities/school for your kid and paying down your mortgage. Note that I am not saying anything about the relative merits of your choices; the important part is to realize that you had choices, you made them, and where you are now is the sum total of those choices.
The primary point of MMM is to design the life you want to live. Most people go through life with a whole list of unspoken expectations, which are usually framed as "needs" -- well, I'm having a kid, of course I need to buy a house; well, my kid is my top priority, of course I need to pay for private school; etc. Even worse are the "deserves," a/k/a, "I've been scrimping and taking care of other people's needs and paying debt for a long time, I deserve a nice, new car." But the reality is that people's needs are quite a bit lower than they think, and no one deserves jack shit except basic human respect and decency. And the bad part about all of this is that in blindly following along with their "needs" and "deserves," most people throw money at things that don't really matter and don't make them happy. Even worse: because those "needs" and "deserves" are right in front of you, right now, they are shiny and pretty, and retirement seems so far away, and there's always time, right? So you end up forsaking Future You's needs for Current You's wants.
What we try to do here is to be conscious of all of those unspoken beliefs, to spend deliberately on the things that matter most. We also work very hard to give Future You a place at the table, and to remind Current You that as shiny and pretty as that thing is, it will not bring nearly as much happiness as financial security and being able to walk away from work whenever we want. You are obviously very very good at living frugally and not throwing money at toys -- and that puts you a huge step in front of many people. But what you need to do is focus a little more on Future You -- a/k/a choose to put saving/investing first, period.
The other thing we focus on here is making mathematically sound decisions with the assets we have. And math is why the choice to invest is better than pre-paying low-interest debt. Reason #1: taxes. Say your marginal tax rate is 20%. If you use that money to pay off debt, you have to make $100 to put $80 toward your debt. OTOH, if you put that money in a 401(k) or tIRA, for that $100 you make, you get invest $100 of it, because none of that counts as income. That alone provides you a significantly larger bang for your buck.
Reason #2 is the power of compounding, which gets just astronomically more powerful over time. Let's use my example from the other thread: you have $40K to invest, and you get 7% return -- in 10 years, that money is worth $80K; $160K in 20; $320K in 30; and $640K in 40. But, you say, that ignores the value of the interest I avoid paying -- yes! It does! So let's consider that: say my interest is 3.5%. First, I pay taxes at that 20% rate, so instead of $40K, I throw $36K at my debt. That means in 20 years, I save $72K; in 40, $144K. So: I "save" $144K -- but I missed out on the chance to earn $640K. If I had invested the money, I could have paid off the debt and had almost half a million bucks left over.
OK, you say, but what if I focus on prepaying the debt now, and then invest after? The answer is in the initial example. If you put the $40K in now, you end up with $640K in 40 years. But if you wait 10 years and then put that same $40K in the market, by the time you reach that 40th year, you have only $320K --
half the amount. Think about that: same amount invested, half the returns -- just because you spent that first decade focusing on the debt.
So, the math says far and away the best option is to pay the minimums on all low-interest debt, and then throw everything you can into a tax-sheltered retirement account. So go do that now. Even if you missed the signup for the 401(k), that's ok -- just focus on maxing out tIRAs for you and your wife every year. That will give you a good chunk of change to get started with -- and decrease your taxes to boot.