rega RB1000 changing cartridges

I've just bought a second hand RB1000 on a P9 table and wonder how most people change cartridges. Is it better to remove the arm (is this easy?)or do it in situ? The person I bought it from said his dealer did it in situ and I know some Linn dealers do although as far as I know Linn do not endorse this practice. But maybe Rega bearings are better? Your thoughts will be most appreciated.
I own two P9/RB1000 TTs. All installations have been performed "in situ", as you put it. One arm is mated with a Rega Apheta; the other with an Ortofon Jubilee. Both installations went well - - - no problems. Personally, I would be hesitant to remove the arm for cartridge installation - - unnecessarily complicates matters and poses a risk of damage to the arm.
I agree. I bought a new Rega RP3 RP303 w/ RP303 arm. I installed a Linn Adikt 6.5Mv MM cart without removing the arm. I also replaced carts on 2 Sondek LP 12's that way. Ittock LVII and Ekos Arm. Just be careful and it won't hurt anything. Linn has something special for everything, so that they can justify taking more of your money. BTW the Rega is as good sounding as both Linn's were at 1/3 the cost. Best of luck.