It is okay to use 4 pads a day as a normal period or menstrual flow often involves using 1 to 7 pads or tampons a day.
Some women only need 3 to 6 a day but may require more on heavier flow days.
10 pads a day occasionally is also not too much when on your period although using 10 pads a day everyday is can be an indication of a heavier than normal flow and could be a possible sign of heavy menstrual bleeding or menorrhagia.
However some women require 6 to 10 pads a day during their heaviest flow days but if you use 10 pads a day daily it may be a sign of heavy menstrual bleeding or menorrhagia which you should see a doctor for.
You should change your pad every time you pee if it has blood or urine on it.
It's not strictly required to change your pad every time you go pee although it's often a good idea for comfort and hygiene and can help reduce odor and potential infections and rashes.
Even if you don't pee, changing your pad frequently helps to maintain cleanliness and comfort, especially during menstruation.
When menstruating or on your period it's recommended that you change your pad every 4 to 8 hours or sooner if it gets full of blood.
Change your pad as often as you need too, especially if it's wet or bloody and you feel uncomfortable.
If you have a heavier flow then you may need to change your pad more often.
And if you're active you may also need to change your pad more often when active.
Also consider your diet and fluid intake as certain foods and increased fluid intake can also affect your bladder and may also require you to change your pad more frequently especially if you leak out some urine into the pad.
You should also change your pad in the morning after you wake up as well.
The heavier your flow on your period the more often you will need to change it and the lighter the flow of your period the less often you will need to change it.