every pg is different and testing 10dpo doesnt not guarantee an accurate result. waiting until your period is late does not make you any less pregnant. tests like clear blue and first response claim to be accurate, but READ THE SMALL PRINT! only something like 43% of women get an accurate result at 10dpo. only 93% of women get an accurate result at 14dpo ffs!
a shocking amount of pg's get a bfp then their period on its due date, why put yourself through it? even internet cheapies are a rip off, because you never quite believe the result, no matter what it is. so you end up getting an expensive one anyway.
its always best to wait until your period is due (better still, til its late) save yourself the heartache and a bit of cash!