It is always nice to have graph paper on hand in order to draw patterns yourself or to rearrange or adapt existing patterns. If you use too many patterns or patterns that are too big, then you will need an overview, and it is handy to have many squares on one sheet. If you make something complicated with many colours or many backstitches, bigger squares are more practical. In other cases, it is recommended to use squares the size of your cross stitches.
You can download this graph paper on A4 format as a PDF file and print it out using Adobe Acrobat Reader (if you do not have this programme, click on the Adobe logo opposite to download it). There are many squared sizes available. The number of grids per 10 cm and per inch are mentioned on the labels. Make sure you print out the page in the actual size to keep the indicated square size.