July 31:
Deadline on BIP141 Technically, on July 31, the miners will have another deadline to avoid a split.
Not later than this date, either activation of BIP91, or fixing of results by BIP141 will occur. In other words, if BIP91 did not reach agreement in time, then a two-week period remains, during which 95% of the miners agreed to activate SegWit.
In reality, there is very little chance that the last day of this period will be on July 31st. And even if this happens, then, most likely, it will be known in advance if the consent threshold will be reached in 95%.
Therefore, as explained above, to prepare for a possible split to users and miners should already from July 29. July 31 is the last opportunity to do something.
August 1:
Activation of BIP148 This day will activate BIP148, and for miners there will be a third and last deadline in order to avoid a split.
August 1 at 03:00 Moscow time (note that in the US will continue on July 31), all BIP148 nodes will start rejecting blocks that did not signal their support for the Segregated Witness protocol (under the terms of BIP141).
If the proposals BIP141 from the team Bitcoin Core or BIP91 from BTC1 will be approved and / or activated in time, then the split of the blockage will not occur.
If no proposal passes, the miners will have the last chance to avoid a split, having independently supported the 
If this happens, there will be two types of bitcoins, which we will call 148 Bitcoin (or 148BTC) and Legacy Bitcoin (or LegacyBTC).
If at the time of the split you will have bitcoins (read: personal keys), you will automatically become the owner of both 148BTC and LegacyBTC. It is likely that new software will be needed to access both types of currency. However, if you are an ordinary user, a reasonable solution is to suspend any transactions, at least until the situation becomes clear. Otherwise, you can lose money.
If the split happens, the miners will have to decide which chain to use (of course, you can still switch at any time - for example, if you want to work with the most profitable chain).