We don't need to invest all the time, we just need to keep some cash to wait for the opportunity to come. A good earning company with up trending stock price would not keep going up all the time. There is always a special event/news that can cause a hiccup on the stock price.
Here is the example:
Wynn Resorts stock price plunged on 26-Jan this year after WSJ reported that dozens of people have been sexually harassed by CEO Steve Wynn.
Facebook stock price plunged on 19-Mar this year after several media reported that Cambridge Analytica, a political consulting firm had unauthorized data access to 50 million Facebook users account.
The chance has come again...
Baidu stock price plunged on 18-May last week after the company announced that Lu Qi, the Chief Operating Officer is stepping down due to "personal and family reasons".
Baidu dip below the support zone 230~240 on 23-May and I bought Baidu
call options on the next day. There is no clear signal that Baidu will bounce from here, it also may retest 230 support again. Anyway, i think 230~240 is a good buying zone.