I’m ok at putting money aside, but im woefully undereducated on fee structure and reasons to move the money to an IRA.
You should try to figure out your fee per fund on both your old and new 401k. You can:
1. Leave the old 401k where it is (if it has low fees) - I did this for a particularly good Fidelity 401k I have.
2. Roll it into your new 401k (if it has low fees) - I did not do this, my new 401k is much worse
3. Roll it into an IRA. But this will make backdoor Roth conversions (including Mega Backdoor Roth) near impossible. It also has implications for bankruptcy protection.
So, it's all about priorities.