Board Thread:Game Discussion/@comment-70.187.46.234-20171031055558/@comment-28169398-20171031060150

Return 340,000 and 20
 * At 0:00 (local time) your ads for the day reset. You receive your daily checkin reward and then there are ads.
 * Ads 1-5 are for
 * Ads 6-25 are for
 * Ads 26-30 are for
 * Ads 31-80 are for
 * Ads 81-85 are for
 * Ads 91-185 are for
 * Ads 186-190 are for
 * No more ads for currency are available until 0:00 the next day.

Depending on how fast you try and do this (within the time constraint of the length of ads) you may be required to go into your devices settings and reset your advertising ID. I assume that  number of ads is tracked by your Account ID, as you will not get more than those 190 ads in that 24-hour period from 0:00.00 to 23:59.59.

Caveat: This in no way effects the number of ads you are allowed to watch for 30% reductions in Repair time or Upgrade times that I have experienced. You may have to refresh your advertising ID, but since starting back playing in release 5.3 I have never run out of ads for 30% Reductions, which can be important for SEs (I can usually finish an LTS in one to two days, so this isn't really an issue there)