Question about adding more data to existing

[lnlarxg]

I am planning on capturing more data on a target I had done before last year 

do I stack old raw files with the new ones captured?

 Or can I actually stack the new raw files,  with the single “stacked” output from the past raw files?

[wimvb]

Calibrate the frames from last year with darks and flats from last year, and the frames from this year with darks and flats from this year. Then stack/integrate all frames together. 

[Pompey Monkey]

What @wimvb advises ^^