It is quite common to see partnerships composed of players at an intermediate, or even at a beginner, level using very complex bidding conventions.
Of course, part of the education of a budding bridge player involves getting acquainted with sophisticated bidding devices, but it is very important to study them thoroughly. To adopt a complex convention without pondering how and when to employ it, and also how to deal with special cases (unforeseen situations), may be counterproductive.
For example, when I ask my opponents something that should be quite simple, such as: How do you react if your Stayman is doubled? Or, How do you react when one of your control-showing cuebids is doubled? The most common response is some perplexity, and a scratching of the head.
This is also the case in carding agreements: leads, attitude and count signals, the suit preference signal, are all situations that require detailed discussion and attention. Going into battle with just a perfunctory verbal agreement may be dangerous.
Since I started playing bridge in the 60's of the past century -- and am therefore basically a bridge dinosaur -- I still play, with most partners, that a high card encourages, and a low card discourages. When I am discussing this with a new partner, I sometimes notice a small surprise, hiding the thought: "how old-fashioned and obsolete..."
That's life. One evening, I would play in a local game with a talented and bold young star. We had only a few minutes to discuss our methods, and he quickly asked, "UDCA [that is, Upside Down Count and Attitude for the uninitiated], right?"
I tried to persuade him to play my way, but he humbly said, "Sorry, that is how I learned to signal, I would not be comfortable playing in any other way", so I relented.
The gods of bridge, being fickle, were listening to our dialogue and decided to have a little fun with us.
At the beginning of the game, the young man had to pick a lead after listening to a weak (12-14) notrump opening and a transfer to spades. The final contract was Four Spades, and the full hand was as follows. He led the Queen of hearts, as West.
When dummy played low, I duly followed suit with the Nine, discouraging in the suit. Declarer won the trick with the Ace, and an unfortunate situation for the defense was established -- no defender could attack this suit again without yielding a trick. It is what we refer to as a "frozen suit".
My clever partner was able to salvage the result. After two rounds of trumps, declarer played a diamond from his hand. West immediately climbed up with his Ace of diamonds, and shot back another diamond, clearly indicating that he didn't have the Ten of hearts (he knew I didn't have that Ten since I had signaled with the Nine; with 109 I would have played the Ten). Nice play!
I did my part in the defense by winning the King of diamonds and refraining to play a heart. When I played the 3rd diamond, declarer was doomed to lose 4 tricks: one heart, two diamonds, one club. Would I have gotten the position right if partner had lazily ducked that diamond trick and allowed me to win the first trick in that suit? Probably not. The heart return looks quite obvious.
A lucky escape, thanks to my partner's acumen, solving a situation engendered exclusively by the unnatural convention of throwing away your high cards.
Some boards later, my partner led the Ace of clubs against Four Spades, after opener started with One Spade and dummt offered a mixed raise (7-9 points, 4 trumps). The full hand was this:
I felt a small sickness in my stomach, but I could not betray a lifetime's instincts, and so I kept my honors and played the Two of clubs . Of course, partner played the King of clubs and another club, and declarer won the trick with the Queen, making his contract. A disaster!
We looked at each other, and he started to mutter "but you encouraged with the Two"... but quickly kept silence after looking at declarer's holding.
Since I said nothing, he smiled ruefully and said "Well, playing UDCA, my lead of the Ace of Clubs forced the defense to lose a trick in this suit! There was nothing else we could do..." I agreed, and he concluded: "I suppose we have to spend some time studying how to deal with special cases such as this one, in which dummy has three low cards after a high honor lead."
I smiled and said "Wise words, but let's have fun tonight. Perhaps there are some other traps lurking in the next boards!"