+1 on the fact that interleaving is the Right Thing To Do, after trimming the quotes to the minimum amount needed.

I don't agree that top posting is easier to read: you may think that no further correspondence will be needed, but maybe the recipient won't agree, and you'll start filling the bottom of the email with a pile of old mails in reverse order, and good luck if one of the messages is long enough to require interleaved answers.

For short messages that don't really need quotes I usually leave just a line of quote to remind what the topic was, but just skipping quotes is also good (and probably easier to do on a phone).

Of course, I use a threaded mail client, so if I need to read old messages I can easily do so (and I don't risk missing pieces in a multi-person conversation because some replies don't include some of the messages which came more or less at the same time).