It depends on what your investment strategy is and holding timeframe, if you're investing for the future, that's you don't have any intentions to sell anytime soon then it doesn't really matter what price you buy provided you'll be holding all through the years to come. There's every possiblity bitcoin would be trading far above the trading price for today in 5-10 years time.

Therefore if I'm planning to be a long term investors I won't mind buying even though the price has increase by some percentage. Where the challenge will be is avoiding the media with all their manipulative fuds as it can influence your decision. That can be done by avoiding articles or discuss that involve the price of bitcoin and just hold unto your coins.