Is 4GB RAM enough in 2016?

I think 4GB is not enough for Sierra and other applications which are running under Sierra.

So your choice is right. I've been using 11inch 8GB MacBook Air.

Good afternoon! You are absolutely right! 4 gigabytes in the real realities aren't enough!!! Itself I have the laptop with 8 gigabytes.

4GB RAM can be very limiting. Apple suggests a minimum of 2GB RAM for the last several instances of OS X however the findings of those forums is 4GB can be a bottleneck with the OS. For even the most minimal use of a device with a occasional multi-tasking 4GB can quickly show it's limitations. Keep the 13 with 8GB, it is a far more viable system for now and going forward.

I don't know about Turbotax or Quicken. Apple's actual specs say 2 GB RAM minimum for its recent lineup of OSX versions but that's probably if you are content with your computer barely booting and maybe running TextEdit. For true barebones you might find 4 GB is enough but my inclination would be to go with 8GB. I guess another consideration is that older computers used spinning platter drives which were slow. If a computer had too little RAM it would revert to using the drive for RAM which slowed it down a lot. Newer computers have flash drives (SSD) which makes them not too much slower should it come down to it, but I wouldn't want to rely upon that. The other thing is your desire to keep the computer for a long time. That alone would suggest to me you shouldn't go with 4 GB. As I said earlier, Apple has been more temperate of late in the need for more RAM with each OSX. It used to be each new OSX required a lot more RAM than the earlier version whereas of late the last couple of OSX versions have all said the same amount. Of course we don't know if that will hold true in the future so buying something that is close to barebones now strikes me as a bit risky for futureproofing.