I close them when they are:
 
Finished in the shop.
WO Bom issued and main Bom's are updated if required.
Outside processing cost are entered. This can take a while. (months)
 
I start with the highest suffix number and work my way down to the -1 WO
 
Then I use JC-A to figure out if it was a winner !
 
Then I edit the routing to get my standard cost in line with the actual cost if required.
 
 

We generally enter finished production when the job is complete.  
 
That said, most of our jobs are relatively small - 1 to 2 days total production time, and the last sequence is completed within a 1 to 2 hour time frame. As Lynn pointed out, if you don't enter FP before POSTING invoices your costs will not be accurate. You can, however, release orders (if you've set the option to allow negative on-hand) and print Packing Slips and Invoices.
 
We post invoices the day after shipping, giving us time to get the Travelers in from the shop and get the Labor and Materials entered. If required (we have a custom program that automatically enters FP for WOs created from a SO, which is roughly half our work) FP is entered at that time. The same person does the posting as does the L&M issue and FP, so when posting invoices they do a lookup of SOs to review what's going to be posted to make sure nothing got missed.
 
One other thing to consider. If your jobs are spread over a longer time period - say you are making 50 items over the course of a week, completing 10 a day - and need to enter FP to do shipments, be aware that DBA/Evo calculates the cost in a way that may not reflect accurately (I don't know how it does it - it doesn't really matter, there's no way that will always work for everyone). On the occasion we need to enter partial FP we manually calculate the cost we want and use that.
 
The only time we close WOs apart from FP (or final FP) is when it gets missed during FP, or if we make less than the WO qty on a WO-from-SO and there is no B/O.