The best way to know when to sell a company, if your intention is to buy on value and sell on realized value, is to simply have an exit plan when you buy. This can be something as simple as "when the stock hits 5 year historical averages from valuation standpoint, I'll move on". Or, it can be as complex as running a discounted cash flow analysis, coming to a fair value, and selling when it hits that fair value.
You have to also accept the fact that you could be wrong in your exit plan and the stock continues to go up. It is something you have to be comfortable with. But having an exit plan and being wrong is much better than not having one at all and guessing. I've sold plenty of stocks that have continued to do well, but I stuck to my plan and it makes things a whole lot easier.
I'll give a prime example of a company I just sold yesterday, that being Alaris Equity Partners. It was placed on the Bull List due to my thoughts on it being a very strong value option and my idea here from my own personal adds was to move on from the company when it hit around 0.9x book value, which is inline with what the company has historically traded at.
I accumulated relatively consistently through 2023/2024 when it traded at 0.7x~ book and just moved on yesterday when it hit 0.9x.
Generally, I don't have an exit plan for many of the stocks I buy as my thesis is simply a buy and hold forever unless something substantial changes. But if I ever have something I am looking to capitalize on in terms of short-term value opportunities, I always develop a plan for when I'm going to exit in the worst case scenario (if it doesn't work out) and when I'm going to exit in the best case scenario (in the case of Alaris, 0.9x book).
In this situation, you didn't really develop any sort of exit plan so it goes from very easy to difficult to decide to move on. What I will say is that I would view most of the pipes as fairly valued here. If you bought on the basis that the stock was undervalued, it is no longer undervalued relative to what the market has paid for it over the last decade or so.
The one thing I will tell you in regards to analyst targets is they are effectively useless. Numerous studies have been done that show they're only right about 30% of the time. With this low of success rate, we can pretty much attribute most of the 30%~ success rate to complete luck. The less you rely on analyst targets, the better.