The Sun stays in each sign for approximately 30 days.The Moon changes signs every 2 ½ days and goes through all 12 signs in approximately 28 days.
Mercury length in each sign changes due to retrogrades. Mercury can be in a sign for 15- 60 days. Because of the retrograde cycles, Mercury is never more than 2 signs away from the Sun at any given time.
Venus stays in a sign from 23 days to 2 months depending on the sign. Venus is also is never more than 2 signs away from the Sun.
Mars changes signs about every 2 months. When Mars retrogrades it can stay in one sign for up to 7 months.
Jupiter stays in each sign approximately 1 year and travels through all 12 signs in 12 years.
Saturn stays in each sign approximately 2 ½ years and takes 29-30 years to travel through all 12 signs.
Uranus changes signs every 7 years and takes 84 years to travel through all 12 signs.
Neptune changes signs every 14 years and takes 164 years to travel through all 12 signs.
Pluto changes signs between 12 and 31 years and takes 248 years to travel through all 12 signs.