Does anyone use "Focus On" during their training? Is the 10% hit that important? It's only a couple of points, right?

Thanks in advance!

Not sure if I'm killing my team or not but I have my entire defense focused on tackling.

Hopefully my stadium will be big enough to handle it next season and if not it will be time to SELL SELL SELL

there is no great mathematical advantage to focus on skills in defense, fitness and tactical as there is only 2-3 skills to deal with but there is certainly advantages to go "all skills" when considering future team balance and wages costs over focussed training.

but attacking skills is different due to the number and variety so focus on your needs but try not to cap out but instead spread the training so don't have a wages bust next season.

I use focus on almost exclusively with the exception of the tactical and kicking skills. the 10% loss is nothing compared to the amount of training lost to an unintended skill in offense or defense. Physicals could be put on general as well but I like to concentrate on Stamina.