I'd think planetary bombardment, especially of the tossing rocks/etc kind, would be VERY rare. Why? Because if it's normalized then your worlds are just as vulnerable. Think of it like a Traveller-esque mutually assured destruction issue. Nukes have only been used twice in combat (so far) in human history because everyone is afraid of them - but that doesn't mean you don't build them or plan to use them. You simply don't use them for fear of the enemy doing the same to you. It's very stupid "logic" - but it's worked thus far. So it seems at least a reasonable assumption that its something that would continue in the future. Slagging someone else's world is actually quite easy - and it's just as easy for them to do the same to you.
I think players aren't realistic about this since it's a game. Kind of like how many people think crews are willingly going to suicide all the time in an effort to "get" the enemy before they die. Fanatical militaries have existed in history doing such things, but it's been more of an aberation than the norm.
Actually blockading a world is going to take a LOT of ships. Think of the volume of space that is occupied by a planet at the 100D jump limit. Sure, you can patrol in close, but that also means you cannot run if you get ambushed yourself by forces from the planet and say arriving at the 100D limit to pin you in if you are too close. Orbital patrols exposes you to planetary defensive fire - and planets are far bigger and can have more of everything than any mobile fleet could ever dream of - essentially unlimited power, unlimited magazine space, supplies, fuel, etc. Blockading means having your own source of supply and repair in someone else's system.
Depending on the station, most are going to be able to withstand sieges for quite some time. Remote locations have always had lots of supplies to cover the time between resupply, often with additional stockpiles to cover for emergencies. The ISS goes many months without a resupply vehicle and can go longer if there are delays. Remote bases have had months, if not years, of supplies laid in because resupply does not occur that often.
Hard to blockade a planet with ships that are incoming since you don't know where or when they will appear. And it takes time for your ships to respond, meaning you could have ships come in as decoys, the blockade fleet moves to intercept and additional ships arrive while you are out of position. Interstellar war with it's inevitable delay of information and inability to see incoming ships makes for some interesting and frustrating tactics. And it's probably going to be very rare to have any actual "deep space" battles since there is nothing of value in a system except for it's planetary objects. No fleet is going to leave it's planet to engage an enemy fleet coming in from say Jupiter (if it's Terra). Defenders will either engage when the enemy is close to Earth or while it's in Jupiter orbit or nearby. Naval engagements away from any place that needs to be defended have always been rare and generally not planned between enemies.