Ironically to me the pace has never really slowed or sped up. Every night I do something to the wee hours of the morning. I haven't had a sleep longer than 5 hours in well over a year now except when I've been out of town because I'm up to 2am or 3am every night doing something. It's just that (and you of all folks I'm sure will agree), when you're building a whole basement around the tank there's a CRAP load of other things you need to take care of at the same time. Not all of it may be tank related.
And of course when you end up redoing something because it doesn't work or doesn't meet your expectations, that I guess will slow things down some, but that's a combination of chance, luck, and not able to accurately forecast all potential side effects of a particular idea. And I'd like to think that could happen to anyone once in a while although I'm fairly certain I've had more than my mathematical/statistical fair share than most might, but that's not worth dwelling on.