Racquets are different. Strings are different. Now strategy is different, and in some cases rightly so (dropshots, serving wide in the deuce court, etc.) teachers are telling players to push their opponent back, instead of going side to side. Bring your opponent in , before it was come to net as much as possible! Before it was hit ur approach shots deep. I could go on and on. Players today have different strengths and weaknesses than 30 years ago. Players used to volley better. Now they return serve better.
The cut off between old school and new school tennis is:
35 & under players play new school
35 & over players play old school
My question is for old school players 5.0 and under. Have you adapted your game to new school tennis? For example the forehand taught now is entirely different than the one taught 30 years ago. Now it’s a whip action. im not convinced these new techniques are better. They produce more power and spin but less control .
I am 69 and think I hit a fairly modern forehand. E/SW hybrid grip, prep with high racket head, small loop on the right (front) of the body, etc... If by "old school" you mean the fairly straight back take back where the racket head points roughly at the back fence and then it is fairly straight forward to contact and the follow through extends out toward the opposing fence - think Connors, McEnroe, Evert, then I don't do that and haven't done that ever. The truth is fairly modern technique has been around since the 1980s - Agassi, Wilander, Courier and others.
I also think at the amateur level, you need to develop an all court game. This is especially true on hard courts. The ability to come to the net, volley and hit overheads on hard courts is invaluable. I don't play a lot of singles in leagues now, but I did very well 10 to 15 years ago and I loved it when I played a young basher that tried to play the heavy topspin ground game. They normally overhit returns so if you can serve, you can get a number of unreturned serves. They don't like it when you come to the net. They tend to not like changes of pace from the baseline as in hit a flatter ball or hit a low slice and you might get an error.
TBH, even in the "modern" game, tennis is pretty much the same as 40 years ago. Get your 1st serve in, hit your ground strokes deep with moderate pace, be aggressive when you get a short ball, come to the net when you get any opportunity, block strong serves back, hit weak serves back aggressively, and lob if you opponent comes to net behind a good ball. Tennis is simple.