Everything depend on your application. You have to take into consideration the duration of the placement, number of installs, goals you want to reach.
There are standard reminders you always have to keep in mind while setting your order:
Our minimum order - is 50 installs (this function was set for our new users to try our service at full and see the minimal result;
Our daily max bound for package installs is 2000 installs per day;
Our daily max bound for keyword installs is 1500 installs per day;
Ordering too many installs - for your application may cause freezing of order and you will have to cancel the order, as the system may crash. That is why we ask to be careful, attentive and listen to all the tips.
*Remember that our support can always help you and give you an advice. Don't hesitate to ask questions related to your orders.