Well done for returning to piano studies. I am presuming that 30 years ago you where either still at school or a young person in your 20s?. 30 years is a long time to take a break. In what way are you struggling?. I am finding that I have difficulty in processing and remembering information. Whereas I could previously play and remember scales etc in my sleep,i now have to really think about key signs and there relative Majors and Minors etc. The same applies to Theory and rhythm patterns. This is probably an age related memory problem for me and the only way to solve it is through sheer hard work,practice and focus. Another problem I am finding is that my concentration span is now very short. So much so that I have to be more or less locked in the room whilst practicing with no distractions whatsoever.
I would take your time learning your pieces and start by playing them slowly,and take one hand at a time and don't put them together until you have completely mastered each passage. Be strict and disciplined with yourself whilst practicing,but don't put to much pressure on yourself. 30 mins a day is better than the odd hour now and again which causes you to miss 2 or 3 days practice consecutively.
Its quite possible that a piece that was deemed Grade 5 in 1987 could now have become a Grade 6, or vice-versa. I have no knowledge of how pieces are Graded but standards are tougher compared to 20 or 30 years ago.
Above all enjoy your music.
If you can afford a teacher then do so. There are far more resources available now,with Apps and online courses and tutorials. You Tube has some excellent videos to watch.
Thanks for the very useful advice, Mike! I gave up entirely when I went to university in the mid-1980s, but I'd plateaued years before, when my homework commitments got out of hand. I did end up with a piano again in my late-20s, but for various reasons never played regularly or really practised at all, and then I was entirely without a piano for 2.5 years after a house move, until we acquired the digital earlier this year.
Some of the problems I'm having seem similar to those you mention -- I find it very hard to learn new pieces, even extremely easy ones. It takes weeks of dedicated practice (slow, hands separately) before it gets noticeably better than a couple of sightreads. I spend literally months working daily at a piece for 20-30 mins, without ever getting to the play through largely without errors stage. I've had to give up on pieces because I'd just exhausted my capacity for practising them without improvement, and when I stop playing a piece daily, I can forget it almost entirely within a few weeks!
I'm also finding I'm playing nearly everything far too slowly, which seems to be at least in part a physical limitation. And I get very tired, achy and even tingly in the forearms and fingers if I play for more than ~30 minutes in a session or about 2 hours in any one day.
I don't know whether exam standards have gone up or down -- I suspect one could find pieces that have moved up a grade as well as those that have moved down. I took Trinity as a child (it was the only board my teacher supported) and I do think some of Trinity's requirements other than pieces back then, ie sightreading and the absence of the grade 5 theory requirement, were easier than ABRSM is currently. On the other hand, Trinity then required four pieces for grades 6 to 8, which I don't believe ABRSM ever has.
I'd love to get a teacher, but I'm having no luck finding one. We've moved to a Scottish island, and the nearest teacher is 1.5 hours drive away (and in any case, full). We don't have proper broadband, so even Skype lessons are out for now! There is a lot of good stuff on Youtube, I know, but it's mixed in with a fair amount of trash, too, in my opinion.
Thanks again for the advice. I will keep at it, and try to feel more enjoyment and less anxiety!