[d0paware]

1) You can anticipate complexity - the what, where, when and why of how it shows up. You are not afraid of it, but...

2) You manage your time well - yours and others'. Figure out when complexity needs to be handled. Respect other peoples' time, they also have important things to do that don't involve you. While you could spend 1 month to figure out the answer to this gnarly bug in open source software after running strace and tcpdump and poring over the linux kernel source code...ask yourself - is this the best use of my time? The answer might still be yes. Just don't forget to look up every once in a while.

3) You prove your skill at 1) and 2) to yourself and others by empirically testing your decisions and evaluating the results.

4) You realize there are trade-offs to every decision you make. This sounds trite until you recognize that things that seem like no-brainers to you aren't, to others. This also applies to how you choose your workplace. Every place I have ever worked at has one really fucking annoying issue, but I have seen enough of these that I can rank them in preference.

5) You are aware of how others perceive you. Peer feedback on your performance should never be a surprise to you. If people were scheming against you, you probably should have known.

I guess after you feel comfortable with these things, you kind of stop caring about the answer to "am I experienced enough?"