Using terry squares during the day time will usually give you a good enough absorbency to allow changing between feeds, and maybe before a nap, without the need to boost, unless you are using budget priced low grade cotton squares. However if you want to use terries at night, or are going to be out for a while, you will possibly need to boost, especially if you use cotton squares.

The best way to boost terries is to just layer up before you fold the square. That way your booster can't slip, and you can place it exactly where you need it. Sometimes just folding 2 squares together as one nappy works best, but this can give you more absorbency than you actually need, resulting in a bulkier nappy than you want. 

Terry boosts are smaller rectangles, which can be layered on top of a terry square but additionally can be trifolded to make a regular 3 layer insert, which will open out to dry quickly. There is an option of 2 sizes and 2 qualities, so you ca adjust exactly as you need. They are all more absorbent than Little Lamb inserts, but no more bulky, and of course dry far more quickly. They are available either as a pack of 10 or individually

Terry boosts can also be used as a really neat but thirsty first nappy for the early days, before BTP nappies will fit. This versatility means you have a really neat fitting but absorbent newborn nappy which can be later transformed into either a triple layer booster/insert for pocket or AIO nappies, or used as a standard terry boost for your terry squares.

These are currently unique to LittlePants.