5 hrs
to work this out you need to do this:
Apple:
$70Ă—2hrs+$25= $165
$70Ă—3hrs+$25=$235
$70Ă—4hrs+$25=$305
$70Ă—5hrs+$25=$375
Local tech shop:
$65Ă—2hr+$50=$180
$65Ă—3hr+$50=$245
$65Ă—4hr+$50=$310
$65Ă—5hr+$50=$375
Now, if you go back and check both the costs you'll see that they are similar after 5 hours.