The discussions here are right on the money. Having spent several
years selling (and milling) hardwood lumber - and many more years using
it for furniture - the ideal milling sequence is:
1 - rough-cut the lumber slightly oversize - I usually allow 1/8" over
in width, and about 1/2" over in length.
2. joint one face flat (using your jointer).
3. thickness the stock using the thickness planer.
4. joint one edge square to a face.
5. saw the final edge square to the remaining face on the table saw.
6. cross-cut both ends square, and to final length.
Having gone through all of this effort to produce good, flat and square
stock, milled to the dimensions you need for your project, it is a good
idea to use stickers between layers of pieces until you are ready to do
final project assembly.