I would like to recommend Sunsama also :) their concept is to put the task into your to do list, then estimate the time and only then to find a time for it in your calendar. And it's also very good to see whether are you trying to squeeze too much tasks into your day (it gives the hint, if your workload is more than 8 hours).

But their prices seemed unreasonable to me ($20 a month), so I've switched to cheaper (and even free, if you don't need premium features) alternative Morgen. But I would highly suggest for everybody who's struggling with setting time for tasks try Sunsama's free trial to see the hints for planning, and switch only then. Or stay, if the price works for you :)

I have no idea how to make it not look like an ad, but yeah, just honest recommendation. Mostly for OP in this thread though

Edit: grammar, hopefully... I'm not sure if it actually improved, but I've tried :)

It's probably because of the small amount. Doctor once recommended me to add a few drops of tea tree oil into water for intimate hygiene, and it worked perfectly. It has antibacterial effect, so it should be beneficial for you :)

But I guess the rule of thumb would be this: when it burns, it's probably not good for you.

Keep in mind, that not everybody is willing to take the hints and some people could just keep thinking that you are busy, but would still be excited to see them.

It's not like you shouldn't follow this advice, it's more like a warning, that sometimes you will see them reaching out to you longer, then one could expect.