It is inconvenient because you can not wash after surgery.
A simple shower is available after 3 to 4 days after surgery.
Before taking a shower, you can apply waterproof bandage to wound area.
Also, after take a shower, simply disinfect and apply ointment.

In case of sauna, enough time should be needed.
If you use the sauna immediately after removing the stitchs, the suture part may be re-opened.
It is usually advisable to remove the stitches after 2 to 3 weeks.
If the incision is wide, it is best to spend about a month. You can also wipe or wash un-operated areas.