No, with Whirlpool using Samourai or Sparrow wallet you don't need to manage every coinjoin manually - you can start with whatever amount, then it is split into 100k (or larger if you prefer) chunks and they are mixed automatically then. You only have to keep the machine running the wallet turned on all the time. First mix happens very quickly, but if you want better anonymity for your UTXOs it's typical to wait for at least 3 mixes for each, and that can take quite a while (usually I had no more than 10 remixes per week, running 24/7).