That's a good tip though everyone has a point and a reason why we're DCAing. And one way to monitor or at least get more encouragement is through checking the price regularly. When it is not advisable to check the prices regularly is if we are at the bear market when you're just mostly on hold position and don't accumulate, so it pretty much don't have difference at all.
Monitoring and cheeking the price of Bitcoin regularly is a traders mindset since if you are investing for a long time purpose three is no need trying to cheek the price of Bitcoin regularly before accumulating Bitcoin and also for investors using the DCA strategy you won't have much need cheeking price of Bitcoin when you can accumulate Bitcoin either weekly or monthly regardless of it's price and continue hodling for long when the price is also at dip it will give you the opportunity to accumulate more Bitcoin.
Sometimes checking the price is not a sign that the investor wants to sell because there are several other reasons why an investor would want to check the price. He might be employing the method of buying the dips which require the investor know when the dips happens to be able to execute the order. You will agree with me that the volatility of Bitcoin is high such that if could cover a big range within few days especially during a period of strong news release. Under this circumstance, the investor might decided to keep tab of the price so he could maximize any opportunity to get into the market, of which I do not see anything wrong here.
Monitoring the price might not always be an indication of someone that wants to sell at the sight of profits because there are more pressing factors that can make an investor sell off his Bitcoin such as not making adequate preparations for emergency funds and investing beyond budgets. These are the real factors that lead to sudden sell offs rather than checking on the price on daily or probably weekly basis.
In the WO mega thread there is the Chatbuddy that updates the price of Bitcoin regularly so anyone active in that thread will always know the price of Bitcoin regularly. Some of the participants there are the OGs who started investing Bitcoin early enough yet they still keep tab of the price not because they want to sell but just for the fun of it.
You are correct, most times the prices are monitored by the investors to target some good prices to buy bitcoin as soon as their discretionary income is available, even before their periodic purchase moment reaches, they might use the price check to monitor the progress of the market and know when its good price for them to make their purchase and try their luck to buying bitcoin for the moment at cheaper price than what might/might not be the price by the time their accumulation period reaches.
for example: someone who regularly buys bitcoin on Sundays may have checked now and seen how bitcoin price has retraced to 69k plus and decide to purchase now before it possibly climbs back to the 70k plus anytime soon and if he is not checking the price, he wouldn't have known about the price correction. Again checking the price progress might help you adequately set purchase orders at prices that would execute naturally when it cuts through them giving you the leverage to buy at the prices you want even when it cuts through those prices in your absence.