Throughout the time I've played over-the-board chess my form has varied. This is an experience I'm sure I have in common with all chess players and, for that matter, anyone who has engaged in anything competitive. I have always put changes in my form down to the circumstances of the time: health, levels of stress at work, problems or joys in my personal life, boredom, enthusiam..... there are lots of variables! But now I'm playing a lot of internet chess I'm beginning to have doubts about that.
I've played and I'm currently engaged in playing quite a number of tournaments on Chess.com with move rates varying form 1 to 5 days. The very odd thing is I find that I'm on form in some of these tournaments and doing well and quite clearly not on form in others. That's despite the fact that the tournaments are being played simultaneously! It also seems to be independent of how many games I'm playing as, although my standard of play slightly reduces if I'm playing too many games, that evens out over all tournaments. I have no explanation for this interesting phenomena.