Spark Plug tubes/o-rings - If one plug is leaking, buy new for all?

[JFP in PA]

Some of the boat transom plugs are not well made and do not grip tightly; not surprising for something that sells for $1. Look for one that has ribs running around its circumference; they seem to work the best. And, you can always add a wrap or two of double sided tape to augment its grip. Just don’t get over ambitious here, they are rigid plastic tubes and will crack if you take the “get a bigger hammer” approach to taking them out………

[2TrunkSteve]

Just like JFP said, I used a cheap transom the first time and had no success. Then I went to a boat shop and bought a much higher quality transom (spent $5). Some came out easier than others. I had to go through the process several times on a few tubes because when I pulled, the plug would pull out and the stubborn tubes wouldn't come with it. I am guessing I was due for this service and I found this a little frustrating. Especially after reading the other experiences that this was no big deal...