For example, I'm 37 years old. My take home after-taxes money is about 30K. I live 2 miles from work. If I drive to work, (I do use my bike some of the time), I use my 7 year old car with 40K miles on it. I don't pay for cable or cell phone. My rent, including heat, is about 10K a year for me (It's about as cheap as it gets to live in northern NJ where housing prices are not an option for me). I make most of my own food and live off about 50 dollars a week in food bills. I don't have kids or any debt. I've accrued about 100K in savings so far.
So...MMM recommends 25 times your annual spending saved up to live off of forever. The thing is, even with my super-frugal lifestyle, I'll never reach that kind of amount before the usual retirement age. I have yet to figure out any kind of investing that isn't risky, I don't really want to risk anything I've worked so hard to save. I'm assuming that nailing the investment strategy would be the essential key, in this case? It's not really possible for me to save any extra significant amount of money than what I already am doing.
Hi - and welcome
You aren't too far from me, and there are others on this board who are in similar circumstances. To start out, yes, there is hope. You certainly won't retire in 4 years on your current salary, but I believe you can reach retirement much earlier than the standard 65 or even 62 years.
A few things first - there is no risk-free investments. Sure, you can stockpile money in FDIC insured bank accounts or buy US treasury bonds, but right now that guarantees low returns that historically won't even match inflation. For most people with long time horizons, investing in a low-cost index fund like the SP500 or total-market fund has the best chance of success - there's never been a 15 year time period when the SP didn't beat inflation, and 90% of 10 year periods beat inflation too. Historically, the Sp500 has given returns of about 7% after inflation.
I mention that because the likelihood of you reaching FI by saving in only "safe" places like savings accounts is virtually nil with your income. But, if you let compounding work for you, the $100k you have already saved could grow to almost $700k by the time you turn 65. That would give you a retirement income about equal to your current income, forever, and that's without any other additions and earning just the historical return of 7%. If you can sock away $3k per year your FI age could be 61.
Finally, I would disagree with you that "nailing the investment strategy [is] key" for you. With your current savings ($100k), how much you can sock away each year is the most important factor in your control, at least now during the acclimation-phase. Later, when you have $300k-$500k in your portolio, returns will become more important.
You mentioned you have $30k post tax and your lodging is about $10k/year (including utilities). that leaves you with $20k. AFter food you have $17,400. Hopefully you are able to save close to half of that - plenty of people around here survive on <$10k/year after lodging, utilities and food. If you are 2 miles from work I question why you'd want to drive ever.
Take heart, keep saving and ask questions.