General retirement advice is to contribute 15% total to your retirement account. Since your employer adds 12%, you should contribute a minimum of 3%.
As for your coworkers advice, it may or may not be valid. Contributing to your 401k or a taxable account, both allow you to invest your money. The 401k comes along with tax advantages. Assuming you are making Traditional contributions, then you are saving taxes at the marginal tax bracket (potentially 22 or 24%). If you contribute enough to drop your MAGI to the 12% bracket, then the tax benefit is much less. You can still contribute to Roth, which means you can withdraw that money tax free in the future but you have to pay taxes on it now.
Another thing to consider is the fees in your 401k. Since you are limited to the options provided, sometimes fees are quite high. If you don’t have any options that cost less than 1%, you likely are better off investing your money elsewhere.
Finally, you get into the really personal part of personal finance. What are your goals? Do you have short/medium term goals that you would prefer to save this money for? For instance, if you want to save up for a down payment for a house in the future, putting that money in a 401k is a bad choice. Do you have a comfortable emergency fund to pay for unexpected expenses? Do you have high interest debt to pay off?
A good resource is this flowchart from r/personal finance: imgur.com/u0ocDRI
You should wait for the statement to pay your spending instead of covering it same day. Otherwise it’s not reported to the credit agencies and it looks like you have no activity on your card.
Also, generally speaking some fluctuation from month to month is to be expected. I wouldn’t worry too much about 10 points in either direction.
Are you budgeting and allowing for fun when you’re in the A phase? If not, or if you are but not at a reasonable level, it might be caused by a reaction to extreme limitations on yourself.
Why should people push for traditional pensions? I don’t want to be stuck at a crappy job just because leaving would reset my retirement clock. It’s the same reason healthcare shouldn’t be attached to the employer either.
I personally have ~1 years worth of cash savings. I have it as an emergency fund plus slush fund for any big purchases so I won’t have to sell my stocks. For instance, I was able to purchase a new HVAC for my house without having to move any money around or sell any investments. I’ve just been slowly replenishing my savings alongside investing since that purchase.
If I was you, I would definitely make sure I have at least 6 months savings and then maybe split investments/continued savings until I was at a point I was comfortable with in terms of savings (whatever it is that you decide that value is). Also, you say your savings account pays low interest. I would look to see if there are any High Yield Savings Accounts available in your country. Here in the US you can find accounts paying ~5% which is great for an efund.
I think at that rate there isn’t a bad decision. Pay it off for the peace of mind. Or, if you have a higher risk tolerance, invest it in the market, since long term it would likely return more than 4.5% (historically speaking, of course). I think keeping the money to keep it in a money market account or CD is probably not worth it, though.